makes 16 servings
For the streusel:
6 tablespoons unsalted butter, melted
1 cup all-purpose flour
1/2 cup light-brown sugar
1/4 teaspoon fine sea salt
For the cake:
1/4 lb rhubarb (about 3 medium-size stalks), rinsed and cut into 1/2" pieces
1/4 lb strawberries (about 5 large berries), rinsed, hulled, and quartered
1 tablespoon light-brown sugar
1 cup unbleached all-purpose flour (separated into 1/4 cup and 3/4 cup)
1/2 teaspoon aluminum-free baking powder
1/4 teaspoon ground cinnamon
1/2 cup unsalted butter, room temperature
1 cup confectioners' sugar
2 large organic eggs
1/2 teaspoon pure vanilla extract
1. Preheat the oven to 350 degrees.
2. Lightly butter an 8" square baking dish. Set aside.
For the streusel:
3. In a small bowl, whisk together the melted butter, brown sugar, salt, and flour. Continue mixing until pebble-sized crumbs form. Place in the refrigerator until ready to use.
For the cake:
4. In a medium-size bowl, combine together the rhubarb, strawberries, brown sugar, and 1/4 cup flour. Set aside.
5. In another medium-size bowl, sift together the remaining flour, baking powder, and cinnamon. Set aside.
6. Use an electric mixer to combine the butter and confectioners' sugar. Continue to beat until light and fluffy.
7. Beat in the eggs one at a time.
8. Stir in the vanilla.
9. Slowly add in the flour mixture. Continue mixing until all ingredients are combined; used a spatula to scrape down the sides of the mixing bowl when necessary.
10. Spread the batter into the bottom of the prepared baking dish.
11. Top the batter evenly with the rhubarb and strawberry mixture.
12. Sprinkle the top with streusel.
13. Bake in the oven for 45-50 minutes, or until golden brown and a toothpick inserted into the center of the cake comes out clean.
14. Let cool on a wire rack before digging in.