Melt butter an allow it to cool (about 10 minutes)
To a large bowl add eggs, granulated sugar, and brown sugar. Using a handle hand held mixer, beat until mixture becomes thicker and a pale color. 2-3 minutes. (You can also use a stand mixer or whisk for this step. A whisk will increase the time the mixture takes to thicken.)
Sift in flour, cocoa powder, baking powder and salt. Mix until flour and cocoa powder are incorporated.
Add melted butter and vanilla. Fold until butter is fully mixed in. The batter should be smooth with no streaks.
Cover batter and chill for at least 1 hour or up to overnight.
Prepare madeleine pan with butter and flour, pan release spray, or other non-stick option.
Fill each section with about 1 tablespoon of batter. Bake at 375 for 8-11 minutes. You'll know your cakes are done with the tops spring back.
Garnish with melted dark chocolate and dried roses.