In a large mixing bowl, beat softened butter with brown sugar until fully combined. Add vanilla and peanut butter, beat until fluffy. Add flour and sweetened condensed milk. Beat until everything is blended well. Fold in the mini chocolate chip morsels.
Press into an 8inx8in baking dish.
In a microwave safe, medium sized bowl, add peanut butter and chocolate chips for the frosting. Melt for one minute. Stir and spread over the cookie dough.
Refrigerate for 3 hours (or overnight). Cut into bite sized pieces. Store in a covered container for up to a week.
Store your Peanut Butter Cookie Dough Bars in a covered container either at room temperature or in the fridge. They'll stay good for about a week.
Make sure to spread the chocolate topping in an even layer over the cookie dough. Use a flat spatula or the back of a spoon to make sure all the parts of the dough are covered.
If you want a straight up peanut butter cookie taste, feel free to leave the chocolate chips out of the dough or replace them with peanut butter morsels.