Nugget approved.
From Just Braise
4 ounces bittersweet chocolate
6 tablespoons butter
1/4 cup sugar
1 teaspoon orange zest
1 egg, separated plus 2 egg whites
pinch of salt
1-1/2 cups grated (cooked) beets plus 2 tablespoons cooking juice
1/4 cup cocoa powder
1) Preheat the oven to 375F. Butter an 8-inch cake pan, line it with parchment paper and butter the parchment paper.
2) In a double boiler set over medium heat, melt the chocolate and butter.
3) With an electric mixer, begin beating egg whites with a pinch of salt and the beet juice. As whites build, add the sugar, egg yolk and zest into the chocolate mixture, stirring to incorporate evenly. Add grated beets to the chocolate and incorporate.
4) Gently fold in the egg whites and cocoa powder until just combined. Pour into the buttered cake pan and bake 25 minutes in the center of the oven.
5) Cake is ready when a toothpick comes out clean on the sides, but slightly wet in the middle. Remove
from the oven and let cool 5 minutes. Invert the cake on a plate and refrigerate 30 minutes before serving.