- Filling:
- 4 cups sliced rhubarb
- 1 1/3 cups white sugar
- 2/3 cup all-purpose flour
- Topping:
- 1 cup all-purpose flour
- 1/2 cup butter, softened
- 1/2 cup firmly packed brown sugar
- Preheat oven to 350 degrees F (175 degrees C). Grease a 9-inch square baking dish.
- Stir rhubarb, white sugar, and 2/3 flour together in a bowl; pour into prepared baking dish.
- Mix 1 cup flour, butter, and brown sugar together in a bowl until mixture is crumbly; sprinkle over rhubarb mixture.
- Bake in the preheated oven until golden brown and bubbling, about 1 hour.