- 3/4 pound rhubarb, trimmed and cut into 1/2-inch lengths on the diagonal
- 2/3 cup granulated sugar, divided
- 1/2 tablespoon lemon juice (zest it for the cake before you cut it)
- 1/4 cup unsalted butter, softened
- 1/4 teaspoon finely grated lemon zest
- 1 large egg
- 2/3 cups all-purpose flour
- 1/2 teaspoon baking powder
- 1/2 teaspoon salt
- 1/4 teaspoon ground ginger
- 3 tbsp sour cream
- 1/2 cup all-purpose flour
- 2 tbsp brown sugar
- 1 pinch salt
- 1 pinch cinnamon
- 2 tablespoons unsalted butter, melted
Preheat oven to 350°F. Coat the bottom and sides of an 8×8-inch baking pan with butter or a nonstick cooking spray, then line the bottom with parchment paper, extending the lengths up two sides. Stir together rhubarb, lemon juice and 1/3 cup sugar and set aside. Beat butter, remaining sugar and lemon zest with an electric mixer until light and fluffy. Add egg. Whisk together flour, baking powder, 3/4 teaspoon table salt and ground ginger together in a small bowl. Add one-third of this mixture to the batter, mixing until just combined. Continue, adding half the sour cream, the second third of the flour mixture, the remaining sour cream, and then the remaining flour mixture, mixing between each addition until just combined.
Dollop batter over prepared pan, then use a spatula to spread the cake into an even, thin layer. Pour the rhubarb mixture over the cake, spreading it into an even layer.
Stir together the crumb mixture, first whisking the flour, brown sugar, table salt and cinnamon together, then stirring in the melted butter with a spoon or fork. Scatter evenly over rhubarb layer. Bake cake in preheated oven for 30 to 40 minutes, until a tester in the middle comes out clean.
Use the parchment “sling” to remove the cake from the pan. Keep at room temperature.
From Smitten Kitchen