I don’t remember when we planted the rhubarb bush, but I do remember a neighbor coming over to warn me that the leaves were poisonous and that I should be sure to keep Joshua away from them. Clearly, she didn’t know my kid – the only green things he ate were gummy bears, Swedish fish and the occasional string bean. Why would Mother Nature make something harmful so temptingly beautiful? Well, at least she gave us the stalks, which are totally safe, thoroughly delicious and in season now.
Rhubarb, which is sometimes – and adorably – called “pie plant,” just about defines tartness. Its flavor is acidic, bright, sharp and sour, which is why it’s almost always cooked with sugar and so companionably paired with strawberries.
I recently looked at the indexes of my cookbooks and was surprised to see how many recipes I’d created with rhubarb – I take this as proof of its boundless versatility. It can be made into compote, jam or sauce, or used in pies, cobblers, crisps and cakes. You can even pair rhubarb with savories – think pork and chicken. It can be baked or broiled, boiled or roasted, and while its texture might change, its personality won't. Rhubarb finishes strong - an admirable quality.
One of my favorite rhubarb recipes is one of the simplest – a soft-crumbed buttermilk cake sweetened with honey, flavored with vanilla and topped with strawberries and rhubarb. The cake is tender, sweet and comforting, and the fruit, which I don’t sweeten, is bracing. I love the contrast!
The last time I made the cake, which was this week, I decided to glaze the top with melted jam – I always have Korean Ginger Tea in the fridge and it easily doubles as a glaze. I turned the cake out of the pan and onto a cooling rack, set it on the counter and walked downstairs to grab a new pastry brush. In the two minutes that I was gone, Michael had cut the hot cake into 16 even pieces (not easy to do nor recommended) and made off with a corner, leaving me to glaze the cake square by square. And then he returned for another square – supposedly a test to see what difference the glaze made. After all these years, he can’t fool me – I know that he’s a cake snitcher masquerading as a scientist. I wrapped the leftovers to take to a neighbor, but not before piling a few onto a plate for my own scientific tasting (and enjoyment).
If you can’t pull rhubarb out of your backyard, grab some at the supermarket. And don’t forget the strawberries.
Happy weekend – I’ll see you on the other side of it.
The rhubarb: The jury’s out on whether or not you should peel rhubarb. I don’t have any hard and fast rules, but if the stalks are thick and wide, I’ll usually peel them. For this cake, you want the pieces of rhubarb to be bite-size – this is the kind of snackable cake you eat out of hand – so you might want to cut chunky stalks in half the long way before you slice the stalks into manageable pieces.
The berries: Because the berries get very soft in the oven, it’s best not to cut them into small pieces. Unlike with the rhubarb, larger is better with the berries.
Extra sugar: I like to scatter the rhubarb and berries over the batter and send the cake into the oven as is. However, if you’d like to sweeten the fruit a bit, you can either sprinkle sugar over the top of the cake before sliding it into the oven or toss the fruit (I’d toss just the rhubarb) with a little sugar. If you want to sugar the rhubarb, do that at the same time that you preheat the oven: Toss the fruit and sugar in a bowl, then when you’re ready for the rhubarb, drain it, pat it dry(ish) and scatter the pieces over the batter.
The glaze: You can use almost any kind of jelly or jam to glaze the top of the cake. In the “red” family, currant jelly works well and, while I’ve never done it, I bet strawberry jam could be good. I usually opt for a “golden” glaze and use apple jelly, apricot jam or Korean honey-citrus tea, which is a jam. Since the layer of glaze is thin, you don’t get much flavor from it – it’s all about the shimmer.
Peakness: The cake is at its very best soon after it’s made. You can nibble on it when it’s just warm or wait for it to come to room temperature. I’ve never turned it away a day later when the fruit has softened and sunk into the cake just a bit – it’s not as pretty as when it’s just made, but it’s still tasty.
Makes 16 squares
1 1/2 cups (204 grams) all-purpose flour
1 teaspoon baking powder
1/4 teaspoon baking soda
1 stick (8 tablespoons; 4 ounces; 113 grams) unsalted butter, at room temperature
1/2 cup (100 grams) sugar
1/2 teaspoon fine sea salt
1/4 cup (60 ml) honey
2 teaspoons pure vanilla extract
1 large egg, at room temperature
1/3 cup (80 ml) buttermilk (well shaken before measuring)
2 cups (200 grams) sliced rhubarb, from 3 to 4 trimmed stalks (see above)
2 cups (200 grams) sliced strawberries (see above)
Jam or jelly, for glazing (see above), optional
Center a rack in the oven and preheat it to 350 degrees F. Spray a 9-inch square baking pan with baker’s spray and line the bottom with parchment paper. (For this cake, baker’s spray works better than butter and flour; if you don’t have it, butter the pan, dust with flour and line the bottom with parchment.) If you want to sugar the rhubarb, start now (see above).
Whisk together the flour, baking powder and baking soda.
Put the butter, sugar and salt in the bowl of a stand mixer fitted with the paddle attachment, or in a large bowl that you can use with a hand mixer. Beat on medium speed, scraping the bowl as needed, until the mixture is smooth, about 3 minutes. Add the honey and beat for another minute or so to blend. Pour in the vanilla extract, add the egg and beat for 2 minutes—don’t be concerned if the mixture curdles.
Turn off the mixer, add half of the dry ingredients and pulse the mixer to begin the blending. Then beat on low until the flour almost disappears into the batter. Still working on low, pour in the buttermilk. When almost all the liquid is incorporated, turn off the mixer, add the rest of the dry ingredients and beat on low until you have a fully blended, very thick batter.
Scrape the batter into the pan. It will take a little nudging to get it into the corners and to smooth the top—do your best to get it even; it will form a slim layer. Scatter over the rhubarb and strawberries. If you want to sweeten the fruit, sprinkle over some sugar (see above).
Bake for 35 to 40 minutes, until the cake, which will be pale in the center and golden at the edges, starts to come away from the sides of the pan; a tester inserted into the center should come out clean. Transfer the pan to a rack and let rest for 5 minutes, then run a table knife around the edges of the pan. Unmold the cake onto a rack, peel away the paper, if you used it, invert again and let cool to room temperature on the rack.
To glaze the cake (optional): If you’d like to glaze the cake, put the jam or jelly in a microwave-safe bowl, add a splash of water and cook for about 30 seconds. Stir and continue to cook in short spurts until the jam is bubbling. Alternatively, you can do this in a saucepan on the stovetop. Use a silicone or pastry brush to paint a skimpy layer of glaze over the top of the cake.
Cut the cake into squares at serving time. With this, a cut-as-you-go strategy is best – the cake will keep better that way.
STORING: The cake is best soon after it’s made, but you can wrap and keep it overnight (see above).
PLAYING AROUND: Of course you can go with all rhubarb (or all strawberries) and then, when rhubarb is no longer in season, you can top the cake with a mix of summer berries. When fall and winter roll in, you can switch to sliced plums, apples, pears or mangoes or segments of oranges, tangerines and/or even grapefruit. Nuts are a welcome addition in any season.