- 6 tablespoons unsalted butter, softened
- 1/4 cup packed light-brown sugar
- 1/4 teaspoon finely grated orange zest, for Rhubarb-Berry Crumbles (optional)
- 1 cup all-purpose flour
- Pinch of salt
Put butter and brown sugar, and orange zest if desired, in the bowl of an electric mixer fitted with the paddle attachment. Mix on medium speed until creamy. Stir in flour and salt. Work mixture through fingers until it forms coarse crumbs ranging in size from peas to gum balls.