Preheat the oven to 350℉ and prepare a mini muffin pan by spraying each well with pan spray.
In a medium bowl, whisk together sugar, butter, eggs, and vanilla extract until the sugar is no longer grainy. This may take up to 5 minutes by hand.
Add the flour, cocoa powder, salt, and baking powder.
Add the mini chocolate chips. Stir to combine.
Bake for 18 to 21 minutes. Let cool slightly in the pan before unmolding.
Notes
If you are worried about the brownies sticking to the muffin pan, you can use parchment paper liners.
Oven temperatures vary and may need to be recalibrated periodically to ensure they are accurate. Make sure to check your brownies at the lower end of the recommended baking time.
To easily remove the bite-sized brownies from the mini muffin tin after baking, use a thin knife or spoon to gently run around each well and carefully lift out each bite.