Preheat the oven to 350°F (175°C).

In a large mixing bowl, combine the softened butter, granulated sugar, and brown sugar. Beat until light and fluffy, about 3-4 minutes.

Incorporate the eggs one at a time, beating well after each addition. Stir in the vanilla extract until fully combined.

In a separate bowl, whisk together the all-purpose flour, cocoa powder, baking powder, and salt. Gradually add this mixture to the wet ingredients, stirring gently until fully incorporated.

Gently fold in the chocolate chips until evenly distributed.

Using a cookie scoop or spoon, drop rounded balls of dough onto a lined baking sheet, spacing them about 2 inches apart. Flatten each ball slightly.

Sprinkle rainbow sprinkles on top of each cookie before baking.

Bake in the preheated oven for 10-12 minutes. Remove when the edges are set but the centers are still slightly soft.

Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.