Ingredients:

  • 6 cups fresh rhubarb, chopped into 1-inch pieces
  • 3/4 cup granulated sugar
  • 2 tbsp cornstarch
  • 1 tbsp all-purpose flour
  • 1 tsp ground cinnamon
  • 1/4 tsp salt
  • 1 cup old-fashioned rolled oats
  • 1 cup all-purpose flour
  • 1/2 cup packed light brown sugar
  • 1/2 cup unsalted butter, chilled and cubed
  • 1 tsp ground cinnamon
  • 1/2 tsp salt

Instructions:

  1. Preheat oven to 375°F (190°C). Lightly grease a 9x13 pan or line with parchment paper.
  2. In a large bowl, toss the chopped rhubarb with granulated sugar, cornstarch, 1 tbsp all-purpose flour, 1 tsp cinnamon, and 1/4 tsp salt until evenly coated.
  3. Pour the rhubarb mixture into the prepared 9x13 pan and spread into an even layer.
  4. In a separate bowl, whisk together the rolled oats, 1 cup all-purpose flour, brown sugar, 1 tsp cinnamon, and 1/2 tsp salt.
  5. Add the chilled, cubed butter to the oat mixture. Use a pastry cutter or fork to work the butter in until the mixture resembles coarse crumbs with pea-sized lumps remaining.
  6. Sprinkle the crumble topping evenly over the rhubarb filling.
  7. Bake for 35–40 minutes until the topping is deep golden mahogany and the fruit juices bubble thickly around the edges.
  8. If the topping browns too quickly, lightly tent the pan with aluminum foil for the final 10 minutes. Remove from oven and let cool.