Rhubarb Upside Down Cake

From Country Living section of Brigton News, June 16, 2022; attributed to Smitten Kitchen.

Topping
• 1 lb rhubarb, trimmed
• 3/4 C granulated sugar
• finely grated zest of 1/2 lemon
• 4 T unsalted butter
• two pinches salt

Cake
• 6 T unsalted butter, softened
• 2/3 C brown sugar
• 1/4 C granulated sugar
• 2 eggs
• 1/2 t vanilla extract
• 2 t baking powder
• 1/4 t salt
• 1 t ground cinnamon
• 1/2 t ground ginger
• 1/8 t ground cloves
• a few gratings nutmeg
• 1/2 C buttermilk
• 1 1/2 C flour

Heat oven to 350 degrees

Make topping: In a 10-inch ovenproof skillet, trim rhubarb to lengths that will fit across the bottom in one direction, some longer and some shorter. Remove from skillet and cut each lengthwise into thin (about 1/4 inch) ribbons (just split thin stalks lengthwise).

Sprinkle sugar into skillet and add lemon zest; mix zest into sugar with your fingers. Add butter and salt and heat over medium until butter has melted, stirring frequently add rhubarb and cook, turning gently, until rhubarb has softened slightly and released some of its liquid, 3 to 4 minutes. Remove from heat.

Make cake: In a large bowl, cream butter and sugar. Add eggs one at a time, beating after each. Add vanilla.

Whisk dry ingredients together. Add buttermilk to sugar-butter-eggs mixture, mix, then add dry ingredients and mix only until combined.

Check that rhubarb covers skillet bottom neatly, then dollop cake batter over it in small spoonfuls as evenly as you can. It will spread out as cake bakes.

Bake until done by toothpick test, around 35 minutes. Let cool on a rack for about 5 minutes, run a knife around the edge to loosen, place a larger plate over the skillet, flip plate and skillet over. If any rhubarb is stuck in the pan or slides down the side, just return it to the top of the cake.