Winter’s harvest brings a barrage of root vegetables, their odd, earthy shapes giving us a glimpse into what goes on in the plant kingdom just below the earth’s surface. Although beets are a familiar root vegetable, many have a hard time remembering what they taste like. Really? I happen to love beets, not only for their sweet taste and texture, but just as much for their extraordinary color. My family does not share this passion, so I am always looking for creative ways to work beets into our diet. Dark chocolate is the perfect partner, not too sweet, but with intense flavor and color. Beets give this single layer cake a rich, moist crumb and an earthy sweetness.
Think deep, rich color and flavor notes, where only a 70% bold, full-bodied dark chocolate will do. Good quality, dark chocolate has a hint of bitterness (a taste still somewhat elusive in the American diet), which is perfectly balanced by the subtle, earthy sweetness in the beets.
Steam the beets until tender. Steaming, rather than boiling, helps retain their exquisite color. Peel and cut into chunk size pieces.
Rough chop into tiny pieces. This is most easily done with a food processor, by pulsing until finely chopped, just short of pureeing. Cover and set aside.
In my world, the scent of melting chocolate has always been reason for pause. A moment to linger, a sensual time out. Matched only by its taste and texture, this nearly perfect food arouses the senses on so many levels. There are only a handful of foods that warrant this type of culinary love affair. Did I really just say that? Add the hot espresso and stir. Mix the chocolate mixture with the butter, gently stirring until the butter has melted and is incorporated. Cover and set aside to cool.
After mixing the beaten egg yolks into the cooled chocolate mixture, fold in the beets and brown sugar until fully incorporated.
Beat/ whisk the room temperature (never cold) egg whites in a separate bowl, adding a pinch of salt when foamy. When the whites become thick enough to hold some shape, begin to add the sugar gradually, only two tablespoons at a time. The sugar needs time to dissolve into the egg whites. Beat just until stiff peaks form, as over beating will cause the whites to de-stabilize and liquefy.
FYI – Beating egg whites, although fairly simple, is somewhat of a right of passage in baking. Science is involved, so a few specifics have to be right on to avoid several things from going very wrong. It’s part of why we love baking, right? The bowl and attachments used to beat the egg whites must be thoroughly clean and dry, as even the smallest amount of fat, oil, yolk or water will render the egg whites flat and inhibit their ability to whip into stiff peaks. Avoid plastic, as it can retain grease and aluminum can give the whites a greyish tone. The acids from a copper-lined bowl help stabilize the egg whites to keep them from liquefying after whipping (better than cream of tartar, vinegar or lemon juice) and give them more loft. When acids are not called for in a recipe, add a pinch of salt when they become foamy to help stabilize. Who knew?
Fold about one third of the beaten egg whites into the chocolate beet mixture. Gently fold the remaining beaten egg white mixture into the chocolate mixture until there are no visible traces of white in the mixture. Do not over mix, as the beaten egg whites will provide some volume and body to the baked cake. Gently fold the flour/ cocoa mixture into the chocolate batter, a third at a time, just until incorporated.
Turn batter into the prepared spring form pan, smoothing out the top. Bake on the center rack of preheated oven for 35- 45 minutes or until a toothpick/ cake tester inserted into the middle comes out clean.
Allow to cool in the pan, set on a cooling rack. Run a spatula around the cake’s edge, between the pan and cake, before releasing the spring. Carefully invert the cake, by placing a cooling rack or plate over the top of the cake, and flipping it upside down. Remove the bottom of the pan, peel off the parchment paper, then turn it right side up onto a cake plate.
Dust the top with sifted powdered/ confectioners sugar and chocolate shavings. If you don’t have a chocolate shaver, you can use a vegetable peeler along the edge of a bar of chocolate. Serve with creme fraiche or whipped cream.