
Easy one pot cookies bars with light and fluffy milk buttercream to leave for the big guy! Santa's going to love these Milk and Cookie Bars!
Preheat oven to 325° F and line a 9"x13" rimmed baking tray with parchment paper. Spray with non-stick spray.
In a medium sauce pan, melt butter over lowest heat until just melted. Remove from heat. Whisk to work any lumps out.
Add brown sugar and sugar. Whisk to combine.
Add egg and vanilla. Whisk to combine.
Add flour, baking powder, and baking soda, and fold in with a spatula or wooden spoon until just combined.
Add mini chips and fold in.
Pour batter onto prepared baking tray and smooth batter so reaches all sides and is somewhat of an even layer.
Bake for 15-20 minutes or until top begins to crack and brown slightly.
Remove from heat and allow to cool in pan for 10 minutes. Carefully invert onto a cooling rack and allow to completely cool.
Beat butter until pale in colour and light and fluffy, about 3-4 minutes.
Add icing sugar, one cup at a time, and beat until incorporated.
Add vanilla and milk and beat until buttercream is light and fluffy.
Cut cookie in half and smear buttercream on the bottom of one piece. Top with other piece and smooth all sides so that they are flush and no buttercream is popping out.
Chill for 15 minutes or overnight.
Cut into 1/2" sticks.