Don't be tempted to substitute unsweetened chocolate or milk chocolate in this recipe. Look for good quality bittersweet chocolate (around 60-72 percent cacao) such as Scharffen Berger, Guittard or Valhrona.
10ounces semisweet or bittersweet chocolate, chopped fine
3/4cupunsalted butter, cubed
5 large eggs
1 1/4cup granulated sugar
5tablespoons coconut flour, almond flour, corn flour, or gluten-free flourplus more for the pan
1 1/2 teaspoonbaking powder
Instructions
Preheat oven to 350 degrees. Butter and flour a 10-inch springform pan.
Over low heat in a heavy bottomed saucepan, stir together the chocolate and butter until smooth. Remove from heat immediately as soon as the chocolate melts.
Beat eggs and sugar together in the bowl of an electric mixer on medium speed (or use a hand mixer) until well blended and starting to thicken. Sift flour and baking powder over the egg mixture and fold it in. Pour in the cooled chocolate mixture and fold in.
Bake for 35-40 minutes until a cake tester comes out mostly clean. Best served slightly warm.
Note: Make a day ahead and reheat, covered with foil, in a 250 degree oven for 15-20 minutes.