Add the melted butter, brown sugar, and granulated sugar to the bowl of a stand mixer and beat until well combined.
Beat in the egg and vanilla extract.
Dump in the flour, baking soda, and salt. Mix until combined. Dough will be soft.
Stir in the dark and white chocolate chips and the sprinkles.
Portion dough into 9 large balls of dough.
Bake for 11 minutes exactly. Do not overbake. Cookies may look a bit underdone, but they will set up as they cool.
Let cookies set on the baking sheet for at least 5 minutes before eating.
Store, tightly covered, for up to 5 days.
Yes, this recipe is written to make 9 cookies. They'll be large bakery style cookies and they're amazing! If you want smaller cookies, adjust the baking time accordingly.This dough doesn't tend to double well. If you need more than 9 cookies, I recommend making separate batches. This recipe requires real butter - do not use margarine.