from Lisa Vega, Dandelion Chocolate Executive Pastry Chef and co-author of Making Chocolate: From Bean to Bar to S’more

YIELD: one 8-inch 4-layer cake

INGREDIENTS:

Cake 
672 grams / 1½ pounds medium red beets
5 large eggs at room temperature
2¾ cups / 570 grams / 20 ounces sugar
½ teaspoon / 2 grams kosher salt
2¼ cups / 226 grams / 8 ounces cake flour, sifted
5 tablespoons / 36 grams / 1¼ ounces ground chocolate, chef’s chocolate, or 70% chocolate finely ground in a spice grinder
butter for the pan

Chocolate Caramel Ganache
2¾ cups / 412 grams / 14 ounces ground chocolate, chef’s chocolate, or chopped 70% chocolate
¾ cup / 150 grams / 5½ ounces sugar
2 cups / 450 grams / 16 ounces heavy cream

DIRECTIONS:

Make the cake
Prepare the beets: Preheat the oven to 350°F (176.7°C). Wrap each beet in foil, and roast the beets for about 1 hour, until a knife pokes easily through the entire flesh. Allow the beets to cool in the foil, and then carefully peel each beet, discarding the skins. In a blender, puree the cooked beets on high speed with 3 tablespoons water until very smooth, a minute or two. Measure out 2 cups plus 2 tablespoons (480 grams / 17 ounces) of the puree, and set it aside. (Reserve the remaining puree for another use.)

Spray or butter two 8-inch round cake pans, line them with parchment, and grease again. In the bowl of a stand mixer fitted with the whisk attachment, whisk the eggs, sugar, and salt on high speed until the mixture becomes pale in color and falls back on itself in ribbons when the whisk is removed,  4 to 6 minutes. Fold in the beet puree until the batter is streaked with color but not completely incorporated.  This will prevent the beaten eggs from deflating too much as you mix the batter.

Sift together the cake flour and finely ground chocolate, then fold them into the batter until just combined. Divide the mixture evenly between the prepared cake pans.

Bake the cakes for 25 to 30 minutes, until a cake tester inserted in the center comes out clean. Allow the cakes to cool completely on a wire rack, and refrigerate or freeze them before slicing the cakes in half horizontally (using a serrated knife) to make 4 cake rounds.

Make the ganache: 
Place the chocolate in a large bowl and set aside. Heat the sugar over medium-low heat in a dry heavy-duty saucepan. Watch it carefully—the sugar on the bottom will begin to melt.  When you see the edges begin to brown, use a heatproof spatula to drag the sugar toward the center to prevent any burning, and continue to stir occasionally until the sugar is completely melted and has turned a medium amber color.

Remove the pan from the heat and immediately start pouring the cream into the caramel in a small, steady stream, while whisking constantly. The caramel will bubble violently and may even seize up slightly, and that’s okay. Continue to whisk, and put the pan back on high heat. As you bring the caramel liquid to a  boil, any seized sugar chunks that may remain should dissolve. Once the liquid reaches a rolling boil, immediately pour it over the chocolate. Let the hot cream sit undisturbed on top of the chocolate for 30  seconds. Then use a whisk to stir slowly at first and then more vigorously as the chocolate and cream combine and the mixture thickens. The ganache should appear shiny and thick, but still be liquid enough to pour. Allow the ganache to fully cool and thicken before assembling the cake.

Using a large offset spatula, spread a thin layer of ganache evenly on top of each cake layer, and layer one on top of another to create a 4-layer cake. Before cutting it, allow the cake to set in the refrigerator, uncovered, for about an hour. The cake will keep in an airtight container at room temperature for several days, or in the refrigerator for up to 1 week.