Preheat the oven to 350 degrees F.
Line an 8-inch square baking pan with two criss-crossed pieces of parchment paper, making sure that the paper is long enough to go up the sides a couple of inches. Grease the parchment paper.
Melt butter in sauce pan. When melted remove from heat. Add cocoa and stir well. Add sugar, eggs and vanilla. Mix until shiny and smooth.
Add flour, baking powder and salt.
Fold in the chocolate chips or chunks, if desired. Pour into an 8 inch pan.
Add as many raspberries you want by placing and pushing gently into batter.
Bake the brownie for about 30-35 minutes or until cooked through. It should no longer wobble in the middle. Leave to cool completely before cutting into squares.
Once the brownies are completely cool, lift the edges of the parchment paper and transfer the brownies to a cutting board. Use a sharp chef’s knife to cut the brownies into squares.