Melt dark chocolate and white chocolate separately using a double boiler.
Whip eggs and sugar until creamy.
Sift together flour, baking powder, and cocoa powder, then mix in.
Add melted dark chocolate and melted butter, and mix well.
Fill madeleine molds about 2/3 full with batter, then place white chocolate chips on top.
Bake in a preheated oven at 170℃ for 12-15 minutes.
Cool in the mold and serve.