Preheat the oven to 400 degrees. Line a cookie sheet with a Silpat or parchment paper. Do not grease.
Stir cake mix and flour in a large bowl. Add cold butter (be sure to dice it into small chunks first) to the flour mixture. Use a pastry cutter to work the butter into the flour mixture, until it is crumbly.
Create a well in the center of the mixture and pour the milk in the center. Stir gently, keeping the dough in the center of the bowl, until the milk is incorporated. Stir only until the mixture comes together (there will be small chunks of butter still, and that’s okay). Stir in chocolate chips.
Sprinkle a small bit of flour over the dough and flour your hands. Turn the dough out onto the prepared cookie sheet. Gently press the dough to flatten into a circle that is an 8 inch diameter. I made mine into a heart, so you can really make whatever shape you want.
Use a greased knife to cut into wedges. Top with sprinkles and gently press them to make them stick.
Bake for 20-25 minutes, until a toothpick inserted comes out clean.