1/2 cup (1 stick) unsalted butter, room temperature
1 cup confectioners’ (icing) sugar
2 large eggs
1/2 tsp pure vanilla extract
Instructions
Preheat oven to 350° F. Line 12 muffin tins with paper or silpat liners.
Make the streusel crumb topping. In a small bowl, beat together the melted butter, light brown sugar and salt. Stir in the cup of flour.
To make the cake. Mix the rhubarb, light brown sugar and 1/4 cup flour in a medium-sized bowl. In another medium-sized bowl, whisk together 3/4 cup flour, baking powder, and salt. Put the butter and confectioners’ sugar in the bowl of an electric mixer and whip until fluffy. Beat in the eggs one at a time. With mixer on a low-speed, beat in the vanilla and the flour mixture, just until blended.
Spoon the cake batter equally into 12 prepared muffin tins. Take small spoonfuls of rhubarb and gently press on top. Sprinkle the streusel topping over each cupcake.
Bake for 12-15 minutes or until the streusel is lightly browned and a toothpick inserted comes out clean.
Adapted from Martha Stewart Rhubarb Crumb Bars
Recipe by Just a Smidgen at https://justasmidgen.com/2012/04/13/oh-streusel-crumbs/