I realize that spring is supposed to be all flowers and pastels, lightness and lemon zest, but all of these cool, rainy days in the last month make me crave winter spices, no matter how many tomatoes and herbs I have planted this week (so many, eee) in hopes, despite all historical evidence, that this is the year I excel at container gardening. And so when a teacher at my son’s school brought me a bag of the most gorgeous, deeply red rhubarb (I really am this lucky), I knew immediately that this cake would have buttery, lightly caramelized stripe-y rhubarb topping draped over it. If you’re ever asking yourself if it’s been too long since you had an upside-down cake, the answer is always yes.
I have learned over the last couple years that there are people — smart, interesting people that I love very much — who do not care for rhubarb. They are not charmed by its perfect coloration (ranging from shimmery garnet through millennial pink, and straight through to mossy green), its tart flavor (that sings against vanilla and lemon and anchors the sometimes cotton candy-sweetness of strawberries so you can better taste them), or by the fact that unlike anything else in my real life (hair, clothes, apartment), it’s incapable of looking bad. They do not see rhubarb as a sign that we’re near done with last winter’s vegetables and that berry season is nigh. They find it jammy or stringy or too wet or depressingly gray once cooked.
I am not here to change their mind, anymore than anyone else has succeeded in convincing me over my lifetime that beets are delicious. I am here for their cake. I’m glad there’s more for the rest of us.
Rhubarb Upside-Down Spice Cake
- 1 pound (450 grams) rhubarb, trimmed
- 3/4 cup (150 grams) granulated sugar
- Finely grated zest from half a lemon
- 4 tablespoons (2 ounces or 55 grams) unsalted butter, cold is fine
- Two pinches of salt
- 6 tablespoons (85 grams) unsalted butter, softened
- 2/3 cup (125 grams) light or dark brown sugar
- 1/4 cup (50 grams) granulated sugar
- 2 large eggs
- 1/2 teaspoon vanilla extract
- 2 teaspoons baking powder
- 1/4 teaspoon fine sea salt
- 1 teaspoon ground cinnamon
- 1/2 teaspoon ground ginger
- 1/8 teaspoon ground cloves
- A few gratings of fresh nutmeg
- 1/2 cup (120 ml) buttermilk
- 1 1/2 cups (195 grams) all-purpose flour
Make topping: In a 10-inch ovenproof skillet, trim your rhubarb to lengths that will fit across the bottom in one direction, i.e. some short and some taller. Remove rhubarb and cut each stalk lengthwise into thin (about 1/4-inch thick) ribbons. If your rhubarb is already quite thin, you might just want to halve each piece lengthwise.
Sprinkle sugar into skillet and add lemon zest; use your fingers to mix the zest into the sugar; the grit of the sugar will help release the most flavor from it. Add butter and salt and heat skillet over medium until butter has melted, stirring frequently. Add rhubarb and cook, turning gently, for 3 to 4 minutes, until it has softened slightly and released some of its liquid. Remove from heat and set skillet aside.
Make cake: In a large bowl, beat butter and sugars until light and fluffy. Add eggs, one at a time, beating until combined, then vanilla. Sprinkle mixture with baking powder, salt, and all the spices and beat well to thoroughly mix them in. Add buttermilk; mixture will have a curdly texture but don’t worry, it’s all going to even out. Scrape down bowl and add flour; beat only until it disappears.
Check your rhubarb base to make sure all the pieces are in the order you’d like them to be; nudge around any that are not, then dollop cake batter over rhubarb mixture in small spoonfuls and smooth top as best as you can. As the rhubarb mixture will be very wet, this will seem almost impossible. I actually gave up and just put it in the oven, where the cake spread into one even layer on its own. (Thank you, cake.)
Bake cake: For about 35 minutes, until a toothpick inserted deep into the cake (but not the topping underneath) comes out batter-free. Transfer to a cooling rack and let cool for 5 minutes, then run a knife around the edges to loosen. Place a larger plate upside down over the skillet and use two potholdered hands to flip cake out onto it. If any rhubarb is stuck in the pan or slides down the side, just return it to the top of the cake cake.
Serve: Warm or at room temperature. Cake keeps for a couple days at room temperature and up to a week in the fridge, or so I hear.