In the bowl of a stand mixer fitted with the paddle attachment, cream together the butter, brown sugar, and granulated sugar till light and fluffy (about 3 minutes). Scrape down sides of bowl as needed.
In a small bowl, whisk together the milk and the vanilla. Add to the butter mixture. Mix till combined, it will be lumpy. Add in the flour and salt. Mix just till combined. Fold in the chocolate chips and sprinkles. Can be stored in the fridge in an airtight container for 2 weeks.