Melt rhubarb, butter, sugar together in a cast iron skillet, then lay down clumps of sturdy dough onto the warm fruit, less like a blanket and more like a dowdy, misshapen comforter. It will feel a lot like a cobbler, and you’ll worry you’re doing something wrong. Put it in the oven.
The cake’s baking soda will pinch hit, making the batter rise on up to cover any spots of rhubarb you may have missed. (In this way, it’s like a tarte tatin you can’t mess up.) It will grow into a cake. Say a quick prayer and flip it upside-down. You’ll wonder again, briefly, if this is actually a cobbler. Trust it.
What you’ll reveal is an underside that’s a mess of girlishly pink, warm rhubarb jam perched smugly on top of a buttery crumb. "Did you think I wasn’t going to work?" it’ll coo.
Heat oven to 375° F. Melt 1 cup of the sugar, 4 tablespoons butter, lemon zest and juice, vanilla, and 1/4 teaspoon of salt in a 9-inch cast iron skillet over medium heat. When the butter and sugar have melted together, add the rhubarb pieces and cook, stirring occasionally, until rhubarb is tender and slightly caramelized, 6 to 8 minutes, depending on the thickness of your rhubarb stalks.
Meanwhile, whisk together remaining sugar and salt, plus flour and baking powder in a bowl. Add remaining butter, and using your fingers, rub into flour mixture to form coarse pea-size pieces. Like Phyllis Grant would say, make like you’re snapping your fingers. Add milk and eggs and stir until a soft, sticky dough forms. If your eggs are on the small side, you may need an extra splash of milk for the dough to come together.
Place pieces of dough over the hot rhubarb mixture, trying to cover the entire surface. It will feel a little like you’re making a cobbler, but the dough will rise up and fill in any holes you’ve left. Bake on a baking sheet until the cake is golden and cooked through, about 30 to 35 minutes. Remove skillet from oven and let the cake rest for about 10 minutes. Place a large, flat serving platter on top of the skillet and invert quickly and carefully. Serve warm or at room temperature with ice cream or whipped cream, if you like, but it’s just as good plain.
I have a thing for most foods topped with a fried egg, a strange disdain for overly soupy tomato sauce, and I can never make it home without ripping off the end of a newly-bought baguette. I like spoons very much.