• 3 cups diced fresh rhubarb
  • ½ cup white sugar
  • 1 tablespoon all-purpose flour
  • 1 tablespoon water
  • 1 teaspoon ground cinnamon
  • 1 teaspoon ground allspice (Optional)


  • 1 cup rolled oats
  • 1 cup brown sugar (packed)
  • ½ cup all-purpose flour
  • ½ cup butter
  1. Gather all ingredients.

    Preheat the oven to 350 degrees F (175 degrees C). Grease an 8-inch square baking dish.

  2. Mix together rhubarb, sugar, flour, water, cinnamon, and allspice in a large bowl until combined. Set aside.

  3. Make topping: Mix together oats, brown sugar, and flour in another large bowl. Use a pastry cutter to incorporate butter into oat mixture until crumbly.

  4. Press about 1/2 of the oat topping into the bottom of the prepared baking dish.

  5. Top with rhubarb mixture; cover with remaining topping.

  6. Bake in the preheated oven until filling is set and top is lightly browned, about 45 minutes.