Strawberry Rhubarb Bars

1 stick + 6 tbsp butter
2 cups flour
½ cup + 1 tbsp brown sugar
½ tsp salt
¼ lb rhubarb, cubed
¼ lb strawberries, sliced
½ tsp baking powder
1 cup confectioner’s sugar
2 large eggs
½ tsp vanilla extract

1. Preheat oven to 350º. Butter an 8×8″ baking pan and line with parchment paper, then butter and flour the parchment paper and tap out the excess flour.
2. To make streusel: whisk together 6 tbsp butter, ½ cup brown sugar, and ¼ tsp salt. Add 1 cup flour and mix with a fork until large crumbs form. Refrigerate.
3. To make cake: in a medium bowl, combine rhubarb, 1 tbsp brown sugar, and ¼ cup flour. In another bowl, whisk ¾ cup flour, baking powder, and ¼ tsp salt. Beat together butter and confectioner’s sugar until light and fluffy, then beat in eggs one by one. With mixer on low, beat in vanilla and gradually add the flour mixture.
4. Spread batter in pan, sprinkle with rhubarb and strawberries, and top with streusel crumble.
5. Bake 45-50 min, until golden and a toothpick inserted into the center comes out with moist crumbs attached. Let cool and cut into squares.