How to Make It
Preheat the oven to 350°. Spray a 10-by-2-inch cake pan with cooking spray. In a bowl, whisk the flour with the granulated sugar, baking powder, baking soda, salt and cocoa powder. In another bowl, whisk the buttermilk with the yogurt and beet. Mix the beet mixture into the dry ingredients. In another bowl, beat the egg whites until soft peaks form. Fold the egg whites into the cake batter.
Scrape the batter into the baking pan. Bake for 55 minutes, until a toothpick inserted in the center comes out clean. Cool the cake on a rack for 20 minutes, then turn it out and let cool completely.
Sift the confectioners' sugar and cocoa powder into a bowl. Whisk in the water until smooth.
Cut the cake into wedges and transfer to plates. Spoon 1 tablespoon of the glaze over each slice. Serve with the raspberries.
One Serving 354 cal, 1.6 gm fat, 0.2 gm sat fat, 78 gm carb, 3 gm fiber.