Step 1

In a medium bowl with a handheld electric mixer or in the bowl of a stand mixer fitted with the paddle attachment, whip together the butter, powdered sugar, brown sugar, flour, salt, milk or cream, and vanilla, until very light and fluffy, 2-3 minutes.

Step 2

Stir in the chocolate chips. Refrigerate until ready to serve; take the frosting out of the refrigerator about an hour before using so it can soften up a bit.