Preheat your oven to 390°F.
Prepare all your ingredients: butter in a saucepan, chocolate in a bowl, egg whites in the bowl of your standing mixer, egg yolks in a bowl, both sugars in a bowl, flour and cocoa powder in a bowl.
Melt butter in a saucepan.
In your standing mixer, whisk the egg whites until foamy. Continue to whisk and add a little bit of the granulated sugar (about 1 oz) and keep beating until they form a peak.
Whisk the egg yolks with both sugars until it become pale yellow, thick and forms a ribbon.
Once the butter is melted pour it on top of the chocolate and mix.
Pour your chocolate/butter mixture on top of your beaten egg yolks and sugar. Mix
Add the flour and cocoa powder and mix.
Gently add the whipped white eggs into the mixture.
Do not overmix.
Transfer batter to baking pan.
Add pecans. Baker for 20 mn