Preheat oven to 350 F.
Line a 9 x 13-inch baking pan with parchment or tin foil and butter or spray with cooking oil.
Melt the butter and set aside.
Using an electric mixer, beat the eggs, sugars and vanilla until well combined. Stir in the melted butter.
Sift together the cocoa, flour, baking powder and a pinch of salt into a second bowl. Add the dry ingredients to the wet, stirring until combined. Pour the batter evenly into baking pan. Give the pan a tap or two on the counter and bake for 45 minutes.
Remove pan from oven and cover hot brownies with toppings. Return to oven for 10 minutes.
Take-out of oven and let the brownies sit in baking pan until completely cooled.
Remove from pan, slice into desired sized pieces and enjoy.