The Forbidden Fruit (Grapefruit Mascarpone Pound Cake)

I was trying to come up with something special for the holiday season, seeking a treat that was not just seasonally appropriate, but also a bit off the beaten path. It seems to me that stereotypical winter desserts always either go straight for the chocolate (not that I can blame them) or some variation of cinnamon, clove, and nutmeg. Those flavors are all well and good, but ever the iconoclast, I set my heart upon creating a grapefruit cake. Moistened with butter and mascarpone cheese, this rich cake allows the delicately sweet-tart perfume of grapefruit to bloom beautifully.

Sadly less pink than I'd hoped

Greenhouses and globalization ensure we can find citrus fruits year round, but the traditional harvest time for most of these semi-tropical treasures is in the winter, likely why clementines were always a requisite stocking stuffer in my family. This means now is the time when citrus fruits are their freshest, juiciest, and cheapest. A bright, acidic splash of citrus is just the thing for perking up all manner of dishes, perking up people in a winter slump, or providing tangy, slightly floral flavors to contrast against the more common stable of wintery desserts. The grapefruit, triumphantly named citrus paradisi, makes an excellent choice for baking due to its sweet, flowery fragrance, tempered in the back with a tiny hint of bitter citrus bite.

Almost paradise

I was always puzzled by the name grapefruit, as the bin at the market does little to evoke images of grapes. The size is off by an order of magnitude, and I've never seen a blushing golden grape, but it turns out the term applies to the fruits on the tree, where their clustered bunches were considered reminiscent of grapes. A hybrid of the pomelo and sweet orange, grapefruit has a few known aliases including shaddock (for the apocryphal sea captain who brought the pomelo seeds that birthed the grapefruit to Barbados) and "the forbidden fruit" (so named by Welsh naturalist Reverend Griffith Hughes, who looked up at grapefruits and saw the golden apples of the Tree of Knowledge). Rather than usher in original sin, however, this cake is just sinfully delicious.

Behold the Bundt

The butter and mascarpone give the cake a plush, velvety texture, at once dense and springy-soft, readily melting on the tongue. The mahogany crust is thick yet moist and tender, yielding under the delicate crackle of sugar glaze to reveal a glowing golden center. The grapefruit flavor is undeniable, but citrus serves as a top note in perfumery for a reason: it doesn't linger long. That's why it's important to include some high-grade vanilla to provide round, warm body notes, helping to meld the opening salvo of grapefruit into the rich background of butter and mascarpone. This cake is delightful still warm from the oven, but will keep equally well tightly covered in plastic in the refrigerator for up to a week. The grapefruit zest continues to distill its flavor into the cake overnight, it's even better the next day.

Pounds of pound cake

Grapefruit mascarpone pound cake

This recipe uses a lot of grapefruit zest, but leaves the fruits otherwise intact. Save them for another recipe, include thin slices as brilliant garnishes, or fan them out directly on top of slices of cake for a succulent contrast.

2 1/2 cups cake flour
1/2 teaspoon baking soda
1 cup (2 sticks) butter, softened
1 cup mascarpone cheese, room temperature
1 1/2 cups sugar
1/2 teaspoon sea salt
3 eggs
2 grapefruits, zested
3 tablespoons grapefruit juice
1 tablespoon vanilla paste, or seeds from 1 vanilla pod

For the glaze:

1 cup powdered sugar
1 grapefruit, zested
2 tablespoons grapefruit juice

Preheat oven to 375 degrees F and butter a 10-inch Bundt pan.

Sift the cake flour and baking soda together into a large bowl, then set aside.

Zesty

Cream the butter, mascarpone, sugar, salt, and grapefruit zest together until light and fluffy. Next, beat in the eggs, vanilla, and grapefruit juice. The mixture will look slightly curdled.

Fold in the flour mixture until incorporated, but do not over mix, the batter will be very thick.

Pillowy-thick batter

Scrape the batter into the prepared pan with a rubber spatula and smooth the top. Place in the oven and reduce the temperature to 325 F. Bake for 55-58 minutes, or until a toothpick or wooden skewer inserted into the center of the cake comes out mostly clean, with just a few loose, clinging crumbs.

Cool 30 minutes in the pan, then turn out onto a wire rack and cool completely.

Golden delicious

To make the glaze, whisk together the powdered sugar, zest, and juice; then drizzle over the cake. Use a pastry brush to sweep drippings back up over the sides.

Cheers!

This post is also available as an article in the Williamsport Sun-Gazette.