What do you get when you cross an orange with a pomelo? A grapefruit! The very first of these love children appeared in the Caribbean during the 18th century, and for a long while all grapefruits had pale yellow flesh. It wasn't until the early 20th century that spontaneous mutations caused red-fleshed grapefruits to appear on trees.
Consumers, it turned out, loved the ruby color, so farmers in Texas and Florida used radiation to induce further mutations. This process led to the creation of the popular Star Ruby and Rio Red varieties.
Grapefruit trees require hot days and warm nights to achieve the perfect balance of sweetness and tartness. They thrive from the Rio Grande Valley in Texas to the dry deserts of Arizona and California. Look for them during the late winter months, especially in February and March, when the fruits are biggest and sweetest.
Grapefruits have a particularly complex aroma — sour and sweet, bitter in an invigorating way, with faint underlying meaty and musky scents. They are wonderful to eat on their own, and they also brighten the flavors of many other foods. Try tossing segmented grapefruit with thick slices of avocado for a simple, delicious salad, or shake up a cocktail of freshly squeezed grapefruit juice, a splash of Campari, and a jigger of gin. For a treat, I like to bake grapefruit-honey cake. The recipe is based on a classic French yogurt cake, which is one of the easiest desserts to prepare. You only need two bowls — one for the dry ingredients and another for the wet ingredients — plus a stirring utensil or two. The finished cake is delightful just as it is, but it's even better drizzled with a mixture of warm honey and grapefruit juice.
I've always loved broiled grapefruit halves. The usual sprinkling of brown sugar on top adds an earthy sweetness to the naturally tart fruit. This cake captures those flavors, and it's a real cinch to make. All French yogurt cakes rely on the same proportion of flour to yogurt to eggs to baking powder. Feel free to swap in other citrus fruits that you love; lemon (with white sugar instead of brown) is classic and dreamy.
1½ cups all-purpose flour
2 teaspoons baking powder
¾ teaspoon kosher salt
1 cup brown sugar
1 tablespoon grapefruit zest
1 cup plain whole milk yogurt
3 large eggs
½ cup neutral-tasting oil, such as safflower oil
3 tablespoons honey
½ cup grapefruit juice
Preheat the oven to 350°F. Generously butter and flour the inside surfaces of an 8 ½ by 4 ½-inch loaf pan.
In a small bowl, whisk the flour, baking powder, and salt.
Measure the brown sugar into a large bowl, then zest the grapefruit directly over the sugar. Using your fingers, rub the zest into the sugar for a minute, or until it smells very fragrant. Add the yogurt and eggs. Whisk vigorously until the mixture is smooth. Dump in the flour mixture, then whisk just until there are no visible lumps of flour. Use a rubber spatula to fold in the oil. When the oil is fully incorporated, the cake batter should have an even, gorgeous sheen. Scrape the batter into the prepared loaf pan. Hold the spatula vertically and drag it lengthwise through the top inch of batter. This subtle gesture creates a seam for the cake to expand. Bake for 55 minutes.
Meanwhile, heat the honey and grapefruit juice in a small saucepot over low heat. As soon as the mixture bubbles, turn off the heat.
When the cake is done, allow it to cool for 10 minutes, then drizzle the warm honey mixture over the top. Sometimes I poke a few holes with a fork to help the cake absorb the honey, but it isn't necessary to do so. To serve, slice the cake into thick pieces and top them with grapefruit segments and sweetened whipped cream or crème fraîche, if you like.