Preheat oven to 350°F (175°C). Grease and flour a 9x13 inch baking pan.

In a bowl, whisk together cocoa powder, sugar, flour, baking powder, and salt.

Stir in melted butter, eggs, and vanilla extract until well combined.

Pour brownie batter into prepared pan and bake for 20-25 minutes.

Let brownies cool completely.

Melt chocolate in a double boiler or microwave, stirring until smooth.

In a separate bowl, cream together softened butter and powdered sugar until light and fluffy.

Beat in vanilla extract.

Gradually add melted chocolate and mix until combined.

In a clean bowl, whisk eggs until very light and fluffy. Gently fold into the chocolate mixture.

Pour the French silk filling over the cooled brownie base. Refrigerate for at least 2 hours or until set.