- ½ cup unsalted butter; melted, plus room temp. butter for pan
- ¾ cup packed light brown sugar
- ¼ tspn. kosher salt
- 1¼ cups all-purpose flour
- ½ lb. rhubarb; cut into ½” pieces
- ½ lb. strawberries; hulled and sliced ¼” thick
- 2 Tbs. light brown sugar
- 1½ cups all-purpose flour; divided
- ¾ tspn. baking powder
- ½ tspn. kosher salt
- ¾ cup unsalted butter; at room temp.
- 1½ cups powdered sugar; plus more for dusting finished bars
- 3 large eggs
- 1 tspn. pure vanilla extract
Preheat oven to 350°. Butter a 9″ square baking pan and line with parchment paper, leaving a 2″ overhang on 2 sides. Butter and flour parchment paper and pan, tapping out the excess flour. Set aside. Whisk together the butter, brown sugar, and salt. Add flour and mix with a fork until large crumbs form. Refrigerate until ready to use. In a medium bowl, combine rhubarb, strawberries, brown sugar, and ¼ cups of the flour. In another medium bowl, whisk the remaining 1¼ cups of flour, baking powder, and salt. In a large bowl, using an electric mixer, beat butter and powdered sugar until light and fluffy. Beat in the eggs, one at a time. With mixer on low, beat in vanilla, then flour mixture. Spread batter in prepared pan. Top with rhubarb and strawberry mixture, then top with prepared streusel. Poke a few pieces up through the streusel to show the rhubarb/strawberries.
Bake for 50 to 55 minutes or until golden brown. Let cool completely in pan. Run a knife around the edge of the pan and, using the parchment paper overhang, lift cake from pan. Cut into bars and dust with powdered sugar. Serve as is, or with some freshly whipped cream.