Pre-heat oven to 350 degrees and line a cupcake tin with 12 papers.
In a medium bowl, whisk together flour, baking powder, and salt.
In the bowl of a stand mixer or in a large bowl with a hand mixer, cream together butter and sugar on medium-high speed until light and fluffy, about 3 minutes.
Add eggs in one at a time, mixing well after each addition. Mix in vanilla extract.
With mixer on low speed, beat in dry ingredients in 3 additions, alternating with the milk. Mix in each addition until just incorporated. Gently fold in chocolate chips and rainbow sprinkles.
Fill cupcake liners about ¾ of the way with batter. Bake cupcakes for 17-20 minutes, until edges are golden and tester comes out clean.
Let cupcakes cool in tin for 5 minutes before moving to wire racks to cool completely.
Once cupcakes are completely cool, core out a small section from the middle (either using a cupcake corer or with a knife). Fill center of cupcake with about a Tbsp of cookie dough.
Fill a pastry bag with frosting, fit with pastry tip (I like to use a Wilton 2A) and frost cupcakes. Top with additional sprinkles and mini chocolate chip cookies.