And now, a case for using citrus. The whole citrus. Pith, peel and all.
This is not without precedent. Here it is in a marmalade; there it is sliced and grilled atop of a fillet of trout. One time-tested use for whole citrus came from the Shakers. In their Shaker lemon pie (aka Ohio lemon pie), thinly-sliced lemons macerate overnight in sugar, to be baked in a double crust the next day for a gooey, sweet-tart confection that's in the class of what my former boss Paula Haney, of Chicago’s Hoosier Mama Pie Company, has called “desperation pies”—the ones you make when there’s literally nothing else around to bake with.
Well. Nothing suggests desperation quite like winter, when the only decent fruit available is citrus (and, I don't know, frozen blueberries?). And while anybody with a Microplane knows the pleasures of the citrus’s skin, few cooks go deeper. They can't be blamed. Given how often we’re warned in recipes to scrape as much of the bitter white pith from the peel as we can, the whole citrus can seem a little...unfriendly.
But it's just shy. Unlocking the flavor of citrus skin (and pith!) just takes a little coaxing, where [coaxing] = [sugar]. The quickest way to soften citrus is to simmer slices in a simple syrup—one part sugar to one part water—until the skin turns translucent, about 30 to 45 minutes. But I’ve had good success lately with a process that’s truly for the lazy: Bring the syrup to a boil, pour it over thin slices of citrus, and let the mixture sit for about a day or two on the kitchen counter.
The results will have many uses: You could, for instance, place lemon slices atop blueberry muffins in their last few minutes of baking. Decorate a chocolate cake with orange slices, or cut them into pieces and fold them into the frosting that you spread between the layers. Chop them up and mix them into granola. Add them to smoothies in the morning, or something stronger later on: A candied orange slice and a splash of the syrup it’s been soaking in are a good beginning to a great old-fashioned. (Follow the rough path laid out here.)
The recipe that follows is for a simple orange upside-down cake, in which the tang of buttermilk in the batter complements the citrus. Think of it as endlessly changeable. You could, for instance, swap out a few tablespoons of flour for cornmeal or polenta, which bring crunch and a subtle sweetness. Add a tablespoon of bourbon, or rum, to the caramel glaze. Add half a teaspoon of pure chile powder to the batter. Or chopped fresh herbs, like rosemary or thyme. Use different fruit: Try blood oranges, or Meyer lemons. Try orange and lemon. Make a lime upside-down cake, adding about a half teaspoon of cinnamon to the batter along with the flour. Or branch out into the noncitrus: A lemon and pear upside-down cake, for instance, with cardamom and a pinch of black pepper in the batter. Or maybe a splash of orange flower water?
Whatever you do, eat it with vanilla ice cream.
