Place the butter and cream cheese in a medium bowl; beat with a mixer until fluffy and thoroughly combined, about 2 minutes.
Add the confectioners sugar, flour, cocoa powder, brown sugar, vanilla extract, and salt. Beat on low speed for 1 more minute or until thoroughly combined.
Add 2 tablespoons of milk and beat for 1 more minute or until combined. If you prefer a thinner texture, add the remaining tablespoon of milk and beat again.
Add the chocolate chips and mix for 30 seconds.
Spoon into a bowl and top with sprinkles. Serve with fruit, cookies and/or pretzels.