Preheat the oven to 350 F. Spray a 9x9 inch square pan with cooking spray. Set aside.

In a double boiler, combine the chocolate pieces and butter. Melt over low heat, stirring occasionally. Once melted, remove from the heat and set aside to cool slightly.

In a small bowl, combine the flour and baking powder.

In a medium bowl, whisk together the eggs, granulated sugar, salt, and vanilla extract. Whisk vigorously until the mixture lightens in color and thickens, about 1 minute.

Add the melted chocolate mixture to the egg mixture, whisking to combine.

Fold in the flour mixture using a rubber spatula.

Stir in the peppermint bark baking chips.

Spread the batter into the prepared pan and bake for 30-40 minutes or until a toothpick inserted in the center comes out clean.

Place the brownie pan on a wire cooling rack. Let cool completely in the pan.

Once cool, use the cookie cutter to cut out Mickey Mouse shaped brownies.

Place the cocoa powder in a medium bowl. Add the butter and stir to combine.

Add the powdered sugar and milk and beat on low until combined.

Stir in the vanilla extract.

Frost the cooled brownies using an offset spatula.

Top with remaining pieces of peppermint bark baking chips