Preheat oven to 400°F. Grease cookie sheet.
Mix flour, sugar, baking soda & salt. Set aside.
Whisk milk, vanilla & eggs. Set aside.
Melt butter & peanut butter, mix with dry ingredients. Add egg mix.
Spread batter on sheet & bake for 20 mins. Cool completely.
For frosting: melt butter & peanut butter, add milk & powdered sugar. Spread over bars.
Let frosting set & serve!
