You can substitute cocoa with chocolate-flavored protein shake.
Melt the chocolate in the microwave in 30-second intervals.
Add all the ingredients to the melted chocolate and mix well.
Divide the batter into portions of 25-26g, place into molds, and microwave for 1 minute.
Keep the microwave door closed for about 2 minutes to let it rest.
It's even tastier the next day.