Brownie

1. Preheat oven to 400°. Spray a 10×15 sized pan (jelly roll pan) with non stick spray. Line bottom with parchment paper and spray parchment with nonstick spray. Set aside.
2. In medium microwave-safe bowl combine cubed butter and chocolate chips. Heat on high for 1 minute in microwave and stir until smooth. Add in vanilla and stir. Set aside.
3. In bowl of stand mixer beat eggs and sugar until pale in color. Add in flour and salt and mix on low until combined. Pour in melted chocolate mixture and stir until incorporated.
4. Spread batter evenly into prepared pan and bake for 8-10 minutes until center is set. Allow pan to cool completely on a wire rack before filling.

Filling

1. Combine all filling ingredients into a mixing bowl and beat until smooth.

Assembly

1. Loosen edges of the brownie from the sides of the pan with a butter knife. Invert pan onto a cutting board, releasing the brownie from the pan. Cut brownie in half with a knife.
2. Spread filling on the bottom side of one of the halves. Place the other half of the brownie directly on top. Cut into squares.