Step 1

Preheat oven to 350 degrees. Line a 9x9 inch square pan with nonstick foil and lightly grease.

Step 2

Melt butter over medium heat. Once completely melted, continue to stir over medium heat for 2-3 minutes until the color changes from yellow to a golden amber color. Remove from heat.

Step 3

In a large bowl whisk flour, cocoa powder, salt, and sugar. Add melted butter, vanilla, and eggs and mix to combine.

Step 4

Pour brownie mixture into prepared pan and bake for 25-30 minutes until an inserted toothpick comes out clean. Allow to cool completely on a wire rack.

Step 5

While the brownie layer is baking, begin to prepare the mousse. Add marshmallows, chocolate chips, and milk to a medium sauce pan and stir over medium-low heat until melted and smooth. Allow mixture to cool while brownies cool.

Step 6

When brownies are cooled, finish the mousse layer. Add heavy cream (it should be very cold straight from the fridge) to a large bowl and mix until stiff peaks form. Add cooled chocolate mixture and mix til smooth. Spread mousse over cooled brownie layer.

Step 7

For the chocolate drizzle (optional) add chocolate chips and heavy cream to a heat safe bowl and microwave on half power for 2 minutes. Stir, and return to microwave (at half power) for 20 seconds at a time stirring after each, as needed til mixture is completely melted and smooth. Allow to cool slightly before drizzling over mousse layer.

Step 8

Chill for at least 30 minutes before cutting into bars and serving.