Place a baking sheet into a buttered 20cm x 20 cm ovenware. Preheat the oven at 175 C
Add the butter, chocolate and cocoa powder into a bowl and melt over a Bain Marie
Add flour, baking powder and salt into a bowl
Mix together the eggs, sugar and vanilla powder in a deep bowl with a mixer for 4 minutes
Add the (cooled) molten chocolate into the egg and sugar mixture. Mix with the mixer until homogeneous
Add the flour mixture onto the chocolate mixture and mix with a mixer until homogeneous
Pour the mixture into the ovenware. Lightly knock the ovenware on the counter for even distribution. Flatten the top with a spatula or spoon
Bake in a preheated (175 C) oven for approximately 35 minutes. Let the brownie rest for 15 minutes before serving