Preheat the oven to 400°F. In a large mixing bowl, mix together the cake mix, dry vanilla pudding mix, eggs, oil, milk, and sour cream with a hand mixer. Mix until everything is just combined, being careful not to over-mix.
Place each ice cream cone in the well of a muffin pan. Fill each cone half full with the prepared batter.
Bake for 14 to 16 minutes or until a toothpick inserted into the center of the cupcake comes out clean.
Remove from the oven and let cool completely before frosting.
In a stand mixer fitted with the whisk attachment, combine the softened butter, powdered sugar, and vanilla. Turn on low and mix until all the powdered sugar is mixed into the butter. Turn on high and whip for 30 seconds until the frosting is light and fluffy.
Place the frosting into a piping bag fitted with a star tip. Frost the cupcakes, and top with sprinkles. These cupcakes are best served the same day they are prepared.
Notes
Cake-style cones are the ones that have a flat bottom rather than a pointed bottom and can easily be found at the grocery store.
A cookie scoop or ice cream scoop would help to fill the ice cream cones with batter while minimizing the mess.
Oven temperatures vary and may need to be recalibrated periodically to ensure they are accurate. Make sure to check your cupcakes at the lower end of the recommended baking time.