This cake appears in Sylvia Thompson’s 1993 Birthday Cake Book. Lemon and chocolate cake batters are swirled together for a light cake with an impossibly soft crumb. An intensely lemony frosting covers the cake, which is finished with splatters of unsweetened chocolate.
The finished result, in the words of Sylvia, “Glints of gold and umber. Tiffany? Pollock? Rembrandt? No, the marbling, frosting, and flavor of this witty Italianate cake.” It is a favorite of mine, served every year at my own birthday. It even got me my first job as a pastry chef after I made it for a wedding in 2016—it’s that good!
Don’t be tempted to swap out the unsweetened chocolate that decorates the cake for a sweetened variety! The bitterness is a sophisticated complement to this light and playful cake—dark or semisweet simply won’t give you the same result. If you don’t have lemon extract (I never seem to), substitute the zest of a lemon or leave it out completely—the cake is equally good without it.
- To make the cake, heat the oven to 350°F. Run the lump of butter over the bottoms of two 9-by-1½-inch round cake pans, smooth a round of waxed paper into each, and then butter the papers.
- Sift the flour, baking soda, baking powder, and salt together.
- In a large mixing bowl, beat the butter on medium speed until creamy. Continue beating while sprinkling in the sugar 1 tablespoon at a time, then beat until very light.
- Add the egg whites one at a time, beating until blended after each, then beat until very light and creamy.
- Add the flour in three parts (sprinkling it over the bowl), alternating with the buttermilk in two parts—beat on the lowest speed manageable and just until each addition disappears. Now fold the batter with a large flexible rubber spatula to finish blending thoroughly.
- Turn half the batter into another bowl. Fold the lemon extract into one batter and the 2 ounces melted chocolate and cinnamon into the other. Divide the batters in half (half for each pan).
- To marble the batters, in each pan, smooth just enough lemon batter over the bottom to cover it. Drop half the chocolate batter in spoonfuls randomly around the pan, then smooth it over the lemon batter with the back of a spoon. Repeat with the rest of the lemon batter and then the remaining chocolate batter. Push the batter slightly up against the sides of the pan. Now, in the center, send the tip of a table knife straight down into the batter—just short of the bottom. Gently lift and turn the knife over, folding the batter together. Repeat every two inches around the pan.
- Bake both pans in the middle of the oven, staggering them on the rack. Bake until a toothpick emerges clean from the center of the cakes, 25–30 minutes.
- Cool in the pans on racks for 15 minutes, then turn out onto the racks, top sides up, to cool completely.
- Make-ahead note: The cake is incredibly light the day of baking but may be wrapped airtight and kept in a cool place for a day.
- Cream the butter in a food processor or with a mixer at medium speed. Gradually blend in the sugar, lemon juice, and cream. Process or beat on high speed until fluffy and light (be careful not to overwork in the food processor, or it will thin out).
- Make-ahead note: This may be prepared a day or two in advance, tightly covered, and refrigerated. If necessary, beat again until creamy before spreading.
- If you have a canelle knife (it makes a groove in the peel by carving out a small strip), cut about 8 grooves from the stem to blossom ends in the lemons, then slice the lemons into rather thin rounds—they’ll loosely resemble flowers.
- Without the canelle knife, slice the lemons into paper-thin rounds, then cut the rounds in half. These half-moons will not resemble flowers, but they will look just as nice decorating your cake.
- Make-ahead note: The slices will keep fresh, wrapped airtight, for a day.
- Up to 6 hours before serving, set the first layer, bottom side up, on a platter. Smooth over 2/3 cup of the frosting, then set on the second layer, top side up.
- Frost the top and sides of the cake.
- When the frosting has set, while someone holds and tips the platter, dip a fork into the remaining 4 ounces of melted chocolate and splash and snap and swizzle it over the sides, then the top.
- Keep on the cool side of room temperature until serving. Just before serving, plant a banner of greeting (a piped greeting would be lost). Make a sunny border of lemon flowers or overlap the halves of lemon slices around the platter, round sides out. Arrange the (preferably lemon-colored) candles.
From The Birthday Cake Book by Sylvia Thompson, edited lightly for clarity
Zola Gregory is a writer and recipe developer based in Seattle. Having previously worked as a pastry chef and baker, she now enjoys helping others find success in their own kitchens through her stories, recipes, and baking classes.