Rhubarb Custard Cake - cooking recipe

Ingredients

4 Tbsp. melted unsalted butter, cooled, plus more room-temperature for pan
1 cup all-purpose flour, plus more for pan
3/4 tsp. baking powder
1/2 tsp. kosher salt
2 large eggs
1 large egg yolk
1 1/2 cups sugar, plus more for sprinkling
1/4 cup sour cream
2 Tbsp. dark rum
2 tsp. finely grated lemon zest
13 oz. rhubarb stalks
A 9\"-diameter springform pan

Preparation

Preheat oven to 350\u00b0F. Butter and flour pan. Whisk baking powder, salt, and 1 cup all-purpose flour in a medium bowl. Whisk eggs, egg yolk, and 1 1/2 cups sugar in a large bowl until very pale and thick, about 1 minute. Whisk in melted butter, sour cream, rum, and lemon zest. Add dry ingredients and fold in until batter is smooth; scrape into prepared pan.
Arrange rhubarb in tight rows over batter, trimming to fit. Don't press fruit into batter-just place over top and let it rest on the surface. Sprinkle with more sugar and bake until cake is golden on top and browned around the sides, 45-55 minutes. Transfer pan to a wire rack and let cake cool in pan 10 minutes. Slide a knife around sides of cake to loosen and unmold. Slide directly onto rack and let cool completely.
Cake can be baked 1 day ahead. Store tightly wrapped at room temperature.