A moist and tender coffee cake filled with tart rhubarb and topped with a buttery streusel crumb, perfect for breakfast or dessert.

Units Scale

Cook Mode Prevent your screen from going dark

Preheat oven to 350°F (175°C). Grease a 9×13-inch baking pan.
In a small bowl, mix rhubarb with 1/2 cup granulated sugar. Set aside.
In a large bowl, cream together butter and 1/2 cup brown sugar until light and fluffy. Beat in the egg and vanilla extract.
In another bowl, whisk together flour, baking soda, and salt. Add to the creamed mixture alternately with sour cream, mixing just until combined.
Fold in the sugared rhubarb and walnuts, if using.
Spread the batter evenly in the prepared pan.
To make streusel topping, combine 1/3 cup brown sugar, 1/4 cup flour, and cinnamon. Cut in cold butter until mixture resembles coarse crumbs.
Sprinkle streusel evenly over the batter.
Bake for 40–45 minutes or until a toothpick inserted in the center comes out clean.
Cool in the pan before slicing and serving.