Some say it’s a fruit; some say vegetable. Some call the whole thing off, using “pie plant” as a preferred moniker. A botanist may tell you it’s a petiole, the technical term for a slender stalk that attaches leaf to stem, or a perennial that grows from a rhizome.
No matter what you call it, just don’t call rhubarb late for dessert. Though it never gets top billing, it’s the real show stealer of any strawberry-rhubarb pie, adding a tart, tangy dimension to each sweet bite. In recent years, rhubarb has taken center stage — in jams, jellies, ice creams, sorbets, tarts, cobblers and all manner of rustic fruit desserts — presenting bright, satisfying seasonal ends to mid-spring meals.
But there’s more to rhubarb than meets the typical consumer’s eye. You’ll often find rhubarb at farmers’ markets and grocery stores with its triangular green leaves shorn off. Full of oxalic acid and anthraquinone glycosides, the leaves are toxic to humans. The roots have been used medicinally for thousands of years, serving as both a fever-reducer and a diuretic. (The stalks are also considered a digestive aid.) In fact, the plant only became a popular food source in eighteenth-century Europe, when sugar became an affordable commodity and the plant could be rendered palatable by the masses.
Now, in the age of molecular gastronomy, chef Grant Achatz of Alinea explores several sugarless preparations in his dish “Rhubarb 7 Different Textures,” which includes a gelée and a dried rhubarb film. My own experimentation with savory rhubarb was not as successful. I cut a stalk into inch-long pieces and stewed it with salt and pepper. The result was, as the French say, “dégoûtante.”
When shopping for rhubarb, look for firm, glossy deep red stalks. Rhubarb also comes in green and pink. They say the color doesn’t affect the taste — but they say a lot of things.
I like the smaller stalks that arc gracefully. The fatter, pinker fuller kind work fine, but they’re not as attractive when sliced. They may also have tougher fibrous strings running the length of the plant, like celery does, which you may want to remove. This kind tends to be “hothouse rhubarb,” grown in the greenhouse to extend the natural growing season.
Around these parts, field rhubarb is available from late April into May. Field rhubarb tends to be tarter. Wrapped in plastic in the refrigerator, it should last for up to ten days. If you don’t plan to use it immediately, cut it into cubes and freeze it in a plastic bag. You can use it for up to six months.
If you’re looking for a place to begin your exploration, here’s a recipe for rhubarb cake I’ve been tinkering with this week. This one is good warm, with vanilla or ginger ice cream, and great the morning after, with a cup of tea.
Double Rhubarb Upside Down Spice Cake
For macerated rhubarb:
1 stalk rhubarb, rinsed and sliced horizontally into 1/8-1/16-inch pieces (approx. 1 cup)
1/3 cup sugar
splash of dry red wine (Chianti works well)
1/2 cup sugar
1/4 cup water
2 T. unsalted butter
2 stalks rhubarb, rinsed
1 1/2 cups white whole wheat flour
1 1/2 t. baking powder
1 t. baking soda
1 1/4 t. ground ginger
1/4 t. ground cinnamon
1/2 t. salt
1/2 cup unsalted butter (1 stick)
3/4 cup sugar
2/3 cup buttermilk
Preheat the oven to 350 degrees.
In a bowl, combine sliced rhubarb and sugar in a medium bowl. Drizzle red wine over rhubarb mixture and stir to coat. Set aside.
In a ten-inch cast-iron skillet, combine sugar and water. Whisk over medium heat until sugar completely dissolves. Raise heat to medium-high and cook, without stirring, until clear bubbles begin to take on golden tinge (five or six minutes). Using a dish towel to grip the handle, swirl the skillet so sugar colors evenly. When sugar is dark golden/light amber in color, remove skillet from heat and immediate whisk in butter. Set aside.
Roll each rhubarb stalk onto its side and slice diagonally into quarter-inch pieces. (The resulting shape looks like a squashed boomerang, or the Star Trek insignia.)
Place rhubarb slices in skillet, beginning at the center of the pan and forming an overlapping spiral that covers the caramel. (While skillet is still warm, you can grease the sides of the pan with a little extra butter.) Set aside.
In the bowl of a stand mixer, cream butter and sugar on high speed with the paddle attachment for three minutes. With mixer still on high, add eggs, one at a time, until fully incorporated. Switch mixer to low speed and add dry ingredients in thirds, alternating with two additions of buttermilk. Remove bowl from mixer.
With a slotted spoon, remove two-thirds of the macerated rhubarb from liquid. Gently fold into batter with wooden spoon, and carefully drop dollops of batter onto prepared rhubarb in skillet. Once all batter is transferred, gently smooth the top, making sure not to disturb rhubarb topping underneath. Remove remaining rhubarb from macerating liquid with slotted spoon and scatter on top of batter.
Bake for approximately 30 minutes, until the cake is deep golden brown and a toothpick inserted in the center comes out clean. Remove from oven and let cool for five minutes. Put cake plate upside down on top of skillet and flip. If any rhubarb sticks to the skillet, replace it on the cake.++