In the wonderful world of bottom-crusted crumb-topped baked-fruit desserts, buckles are new to me. And I’m a fan. I love how the crispy top melts into the stewed fruit, which all sinks into the base. And I like that I can eat it as I would a brownie, out of hand, making for easy snacking morning, noon and night.
- 13 ounces rhubarb, trimmed and cut 1/2 inch thick on the bias
- 1 cup sugar, divided
- 1 cup all-purpose flour
- 1/2 teaspoon baking powder
- 1/2 teaspoon salt (I used table salt)
- 6 tablespoons unsalted butter, softened
- 1 teaspoon finely grated lemon zest
- 1.5 large eggs*
- 1/2 teaspoon pure vanilla extract
- 1/4 cup sour cream
*The doubled recipe calls for 3 eggs, so I whisked up 3, weighed them, and used half, which was about 1/3 cup or 2 7/8 ounces.
- 1/2 cup all-purpose flour
- 2 tablespoons light-brown sugar
- 1/2 teaspoon salt
- 4 tablespoons unsalted butter, softened*
*I’ve upped the amount of butter here and changed it to softened rather than melted. I think the crumb topping needed more butter, and I like using softened butter in a crumb topping.
- Preheat oven to 350 degrees, with rack in center position. Line a 9-inch square cake pan with parchment paper. Stir together rhubarb and 1/2 cup sugar; set aside to macerate.
- Whisk together flour, baking powder, and salt. Beat together butter, remaining 1/2 cup sugar, and the lemon zest until light and fluffy. Beat in eggs, a little at a time, then beat in vanilla. Beat in flour mixture in 2 additions, alternating with sour cream, beginning and ending with flour mixture.
- Crumb topping: Stir together flour, brown sugar, and salt. Add 2 tablespoons of the butter and mix up with your fingers until clumps form. If it’s looking dry, add another tablespoon of butter and mix again until clumps form. Add remaining tablespoon of butter if necessary.
- Spread batter into pan. Top with rhubarb mixture, and sprinkle with crumb topping. Bake until golden on top and cooked through, about 1 hour 5 minutes. Let cool completely in pan on wire rack, then lift cake from pan using parchment. Remove parchment. Before serving, cut buckle into 2-inch squares.