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gluten-free rhubarb crumble bars cut into squares, on parchment paper

Gluten-Free Raspberry Rhubarb Crumble Bars

These tasty gluten-free rhubarb bars a fruity raspberry rhubarb filling in between an oat crust and oat crumble topping. They're an absolutely delicious way to bake with rhubarb!
5 from 7 votes
Prep Time :20 minutes
Cook Time :45 minutes
Total Time :55 minutes
Yield: 14 bars
Author: Amanda Paa





  • 2 cups diced rhubarb (frozen or fresh) (225 grams)
  • 1 1/4 cups organic raspberries (frozen or fresh) (170 grams)
  • 1/3 cup + 1 tablespoon raw cane sugar
  • zest and juice of one lemon
  • 3 teaspoons cornstarch or tapioca starch
  • 1/2 teaspoon vanilla extract


  • For the compote, combine rhubarb, raspberries, sugar, lemon zest and juice in a heavy bottom saucepan over medium heat. Bring to a hard boil, stirring, and let simmer for 10 minutes. Add cornstarch or tapioca starch, and stir to dissolve. Let cook for 3 minutes longer, until mixture has thickened slightly. Stir in vanilla. Remove from heat and let cool for 15 minutes.
  • Meanwhile preheat oven to 350 degrees F. In a large mixing bowl, whisk together oat flour, oats, brown sugar, tapioca starch, baking powder, sea salt and cinnamon. Stir in butter and mix well so that no white streaks remain.
  • Using the back of a spatula or spoon, firmly press a heaping cup of oat mixture into a parchment lined 8x8 baking pan. I find a spoon works really well to press it together and get it smooth.
  • Prick crust with fork a few times. Bake for 12 minutes, until crust is fragrant and lightly browned. Remove from oven and let cool for 10 minutes.
  • Top with 1 1/4 cups of rhubarb compote, then sprinkle the top with the rest of the oat mixture. Bake for additional 25-30 minutes, or until topping is browned. Set aside to cool, then refrigerate. Then cut. They taste best this way! And it gives them the best texture, firm and sturdy.