Key Lime Lush (No-Bake, Real Key Lime Custard)

Close-up of creamy Key Lime Pie Lasagna showcasing distinct layers of graham cracker crust, cream cheese filling, smooth key lime layer, and fluffy whipped topping sprinkled with graham cracker crumbs and fresh lime zest.

A no-bake, layered dessert with a graham cracker crust, cream cheese layer, real cooked key lime custard, and whipped topping.

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Table of Contents

Ingredients For Key Lime Lush
How to Make Key Lime Lush
Tips For Perfect Lime Lush
Storage FAQ
More Layered, No-Bake Dessert Recipes
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FAQ

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Key lime lush is a no-bake, layered dessert: graham cracker crust, cream cheese layer, tangy lime filling, and whipped topping on top. Most recipes get that lime layer from a box of instant pudding. But I found the boxed versions ended up overly sweet and tangy without any real depth of flavor.

Instead, I created a lime filling that's real custard, cooked on the stove with egg yolks, sugar, and fresh key lime juice. It takes a bit more time than stirring in a pudding packet, but it tastes like actual key lime pie instead of lime-flavored pudding. If you've made a lush dessert before and felt like something was missing from the filling, this is probably it.

Slice of Key Lime Pie Lasagna on a white plate with graham cracker crust, creamy layers, whipped topping, lime zest, and a fresh lime half.

Ingredients For Key Lime Lush

Ingredients for Key Lime Pie Lasagna arranged on a white background, including cream cheese, whipped topping, graham cracker crumbs, lime juice, lime zest, egg yolks, powdered sugar, granulated sugar, butter, cornstarch, vanilla, and green food coloring. Text overlay lists ingredient amounts and measurements.

Crust

2½ cups graham cracker crumbs
3 tablespoons granulated sugar
½ cup salted butter, melted

Cream cheese layer

10 ounces cream cheese, softened
1½ cups powdered sugar
1½ teaspoons vanilla extract
1½ cups whipped topping, thawed

Key lime filling

5 egg yolks, lightly beaten
1½ cups granulated sugar
4½ tablespoons cornstarch
¾ cup fresh key lime juice (about 12 key limes)
½ cup salted butter, melted
2½ cups whipped topping, thawed
3 to 4 drops green food coloring (optional)

Topping

2 cups whipped topping, thawed
1 tablespoon lime zest, for garnish (optional)
2 tablespoons graham cracker crumbs, for garnish (optional)

A few notes on ingredients:

Regular, fresh-squeezed lime juice can stand in for key lime juice in the same amount. Key limes have a slightly more floral, tart edge, but the difference is subtle once everything else is mixed in.

Nellie & Joe's Key West Lime Juice makes a decent substitute for fresh key limes in this recipe. I don't recommend plain old bottled lime juice, but a good-quality key lime juice can certainly work.

Prefer a different crust? Crushed Oreos or vanilla wafers both hold up well under the cream cheese layer and pair nicely with the lime flavor.

Green food coloring is there for color only. Skip it if you'd rather the filling stay its natural pale yellow.

How to Make Key Lime Lush

Make the crust

Stir the graham cracker crumbs, sugar, and melted butter together in a bowl until the mixture looks like wet sand.

Press it firmly and evenly into the bottom of a 9x13-inch baking dish.

Bake at 350°F for 6 minutes, then set it aside to cool completely.

Graham cracker crust pressed into a 9x13 baking dish

Make the cream cheese layer

Beat the softened cream cheese on medium-high speed until smooth, about a minute. Add the vanilla and beat until combined, then mix in the powdered sugar on low speed until no streaks remain.

Fold in the whipped topping by hand until the mixture is light and no white streaks remain.

Cream cheese mixture beaten smooth in a glass bowl with a hand mixer — Use a spatula for this part - it will keep the filling light and airy. Using a hand mixer to incorporate the Cool Whip will deflate it and make the filling heavy and thick.

Spread it evenly over the cooled crust, cover, and refrigerate while you make the lime layer.

Cream cheese mixture being spread over the graham cracker crust

Make the key lime filling

In a saucepan over medium-high heat, whisk together the sugar and cornstarch. Whisk in the key lime juice, melted butter, and egg yolks. Keep whisking constantly.

The mixture will look thin at first, but it will start to simmer and thicken, going from watery to a consistency closer to pudding, usually within a few minutes. Once it coats the whisk and holds its shape when you drag it through, it's done.

Key lime custard mixture whisked together in a saucepan before cooking

Take it off the heat right away. Cooking the yolks fully here matters: it's what gives this filling its custard texture instead of a loose, runny one, and it's the difference between this and versions made with raw eggs or instant pudding mix.

Cover the saucepan and refrigerate the custard for about 2 hours, until it's completely cold.

Once it's cold, fold in the whipped topping and the green food coloring. Spread it over the cream cheese layer.

Key lime filling with whipped topping folded in, tinted pale green — Be sure to use a spatula to fold in the Cool Whip here, too.

Add the topping and chill

Spread the remaining whipped topping over the lime layer.

Whipped topping being spread over the key lime layer

Cover tightly and refrigerate for at least 6 hours, or overnight. The dessert needs this time for the layers to set firmly enough to slice cleanly.

Just before serving, sprinkle with graham cracker crumbs and lime zest, if using.

Key Lime Pie Lasagna in a glass baking dish with a slice removed, revealing layers of graham cracker crust, cream cheese filling, smooth key lime pudding layer, and whipped topping garnished with lime zest and graham cracker crumbs.

Tips For Perfect Lime Lush

Let the crust cool completely before adding the cream cheese layer. If it's still warm, the cream cheese layer will start to melt and won't set properly once chilled.

Make sure the cream cheese is fully softened before mixing. Cold cream cheese leaves lumps that don't smooth out, even with a long beat. Leave it at room temperature for about an hour, or use short bursts in the microwave if you're short on time.

Whisk the custard constantly while it cooks. It goes from thin to thickened fairly quickly once it starts to simmer, and it can scorch on the bottom of the pan if it sits unstirred for even a few seconds.

Cool the custard completely before folding in the whipped topping. Folding Cool Whip into warm custard deflates it, and can make the lime layer runny instead of fluffy.

Add the green food coloring a drop at a time. It takes very little to get a pale, natural-looking green. Too much and the filling starts to look artificial.

Don't skip the chill time. Six hours minimum, overnight if you can. This dessert needs that time for the layers to firm up enough to cut clean slices instead of collapsing.

Storage FAQ

Storing leftovers: Cover the dish tightly or transfer slices to an airtight container. It keeps in the refrigerator for up to 4 days. The crust softens a bit over time but stays fine to eat.

Freezing: This dessert is best enjoyed fresh from the fridge, but it can be frozen if needed. Freeze individual slices on a tray until firm, then wrap tightly and store in a freezer bag for up to 1 month. Thaw overnight in the refrigerator. Keep in mind, the texture softens and can get slightly watery once thawed, especially in the whipped topping and crust, so it won't be quite as clean-cut as a fresh slice.

Slice of Key Lime Pie Lasagna lifted on a spatula, showing distinct layers of graham cracker crust, cream cheese filling, creamy key lime layer, and whipped topping sprinkled with lime zest and graham cracker crumbs.

More Layered, No-Bake Dessert Recipes

If you're into lush-style desserts, you'll probably also like Cherry Cheesecake Lush and No-Bake Chocolate Cherry Lush.

For more layered, no-bake options in the same lasagna-style format, try Lemon Lasagna, Peanut Butter Lasagna, White Chocolate Lasagna, or Candy Cane Lush Recipe.

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Key Lime Lasagna

A no-bake, layered dessert with a graham cracker crust, cream cheese layer, real cooked key lime custard, and whipped topping.

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Prep Time 9

Cook Time 30

Chill Time 8

Course Dessert

Cuisine American

Servings

Calories 591 kcal

Ingredients

Crust

2½ cups graham cracker crumbs
3 tablespoons granulated sugar
½ cup salted butter (melted)

Cream cheese layer

10 ounces cream cheese (softened)
1½ cups powdered sugar
1½ teaspoons vanilla extract
1½ cups whipped topping (thawed)

Key lime filling

5 egg yolks (lightly beaten)
1½ cups granulated sugar
4½ tablespoons cornstarch
¾ cup key lime juice
½ cup salted butter (melted)
2½ cups whipped topping (thawed)
3 to 4 drops green food coloring (optional)

Topping

2 cups whipped topping (thawed)
1 tablespoon lime zest (for garnish (optional))
2 tablespoons graham cracker crumbs (for garnish (optional))

DIRECTIONS

Preheat oven to 350°F. Stir graham cracker crumbs, sugar, and melted butter together until it looks like wet sand. Press evenly into a 9x13-inch baking dish and bake for 6 minutes. Cool completely.
Beat cream cheese until smooth, about 1 minute. Add vanilla and mix in. Beat in powdered sugar on low speed until no streaks remain. Fold in whipped topping until light and fully combined.
Spread over the cooled crust. Cover and refrigerate.
In a saucepan over medium-high heat, whisk together sugar and cornstarch. Whisk in key lime juice, melted butter, and egg yolks. Cook, whisking constantly, until the mixture simmers and thickens enough to coat the whisk, about a few minutes. Remove from heat immediately.
Cover and refrigerate the custard for about 2 hours until completely cold. Fold in whipped topping and green food coloring.
Spread the key lime filling over the cream cheese layer.
Spread remaining whipped topping over the lime layer. Cover tightly and refrigerate at least 6 hours, or overnight.
Garnish with graham cracker crumbs and lime zest, if using, just before serving.

Notes

This dessert needs the full chill time, at least 6 hours and ideally overnight, for the layers to set firmly enough to slice cleanly. Cutting it too early will give you messy, sliding layers.
Make sure the crust is completely cool before adding the cream cheese layer, and make sure the custard is completely cold before folding in the whipped topping. Skipping either of these can keep the layers from setting properly.
Leftovers keep in the refrigerator for up to 4 days, covered tightly.

Nutrition

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FAQ

What's the difference between key lime lush and key lime pie?

Key lime pie is a single pie crust filled with a baked or chilled key lime custard. Key lime lush is a layered, 9x13 dessert with a graham cracker crust, a cream cheese layer, a key lime layer, and whipped topping on top. The flavors overlap, but the lush version has more layers and is meant to be cut into squares rather than wedges.

Can I use a store-bought crust?

Premade graham cracker crusts are usually sold in 9-inch pie or springform pans, not 9x13, so they won't fit this dish as-is. The easiest shortcut is store-bought graham cracker crumbs instead of crushing your own, but the crust itself still needs to be made and pressed into the pan.

Can I use regular lime juice instead of key lime juice?

Yes, at the same amount. Key limes have a slightly more floral, tart edge, but regular lime juice works well and the difference is subtle once the filling is mixed with the other ingredients.

How long does a lush dessert need to chill?

At least 6 hours, and overnight is better. The layers need that time to firm up enough to hold their shape when sliced. Cutting it too early usually results in messy, sliding layers.

Can this be frozen?

It can, though it's best enjoyed fresh from the fridge. If freezing, wrap individual slices tightly and store for up to 1 month, then thaw overnight in the refrigerator. The texture softens slightly after thawing, particularly in the whipped topping and crust.

Why isn't my filling setting?

This usually means the custard wasn't cooked long enough before it was taken off the heat. It needs to come to a simmer and visibly thicken, enough to coat the whisk and hold its shape briefly, before you remove it from the heat. If it's pulled too early, it stays loose even after chilling.

Key Lime Lush Recipe

Ingredients For Key Lime Lush