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delicious plum-oatmeal crumble bars in a stack with Christmas decorations

Plum-Oatmeal Crumble Bars

  • Author: Beth
  • Prep Time: 45 minutes
  • Cook Time: 60 minutes
  • Total Time: 1 hour 45 minutes
  • Yield: 16 bars 1x
  • Category: Cookie, bar
  • Method: Oven, Stovetop
  • Cuisine: American

Description

These gluten-free, vegan plum-oatmeal crumble bars have a delicious oatmeal-almond crust and crumble topping. The mildly sweet, cinnamony crust makes a great flavor contrast with the tartness of the simple homemade plum jam filling. 


Scale

Ingredients

For the crust and crumble

  • 1¾ cups blanched almond flour
  • ½ cup gluten-free rolled oats 
  • ½ cup oat flour (see note)
  • ¼ cup coconut flour
  • 1/2 teaspoon cinnamon (+ pinch nutmeg, optional)
  • 45 tablespoons coconut sugar
  • ⅓ cup coconut oil, melted
  • ¼ cup almond butter
  • 3 tablespoons water
  • oil for greasing pan (I like MCT)

For the plum filling

  • 3 cups fresh plums, pitted and chopped into small chunks (I used about 20 small (1½-inch) red plums
  • 2 tablespoons coconut sugar
  • 1 tablespoon tapioca flour (plus an extra tablespoon is you want the filling thick) 
  • 2 teaspoons Vanilla extract (see how to make your own!)
  • ¼ teaspoon cinnamon
  • ¼ teaspoon nutmeg

Instructions

  1. Preheat oven to 350°F and line an 8×8-inch square pan with parchment paper. Oil lightly (I like MCT oil for this).

For the plum filling

  1. Add the plums to a saucepan over medium heat. Stir in the coconut sugar, tapioca flour, vanilla, and cinnamon. Cook down the chopped plums for about 30 minutes or until they’re mostly broken down and reducing. Stir frequently so that the tapioca doesn’t stick to the bottom of the pan. If you want them completely smooth, use an immersion blender for a few seconds to blend up the skins (I don’t find that blending is needed).
  2. Cook the blended plum mixture for 15 minutes or until it becomes a thick paste. When you run a spoon through the center, it should take a second before the paste flows back into the middle. 

For the crumble

  1. While the plum mixture is cooking, stir the almond flour, gluten-free rolled oats, oat flour, coconut flour, coconut sugar and cinnamon/nutmeg together in a mixing bowl.
  2. Warm the coconut oil and almond butter, and stir them together. Pour the mixture into the dry ingredients, and stir until the dry ingredients are completely mixed with the almond butter and oil. 
  3. Add water by tablespoons until the dough is moistened and it sticks together but is still a little crumbly. In my kitchen, this took 3 tablespoonfuls until a handful of the crust would stick together but could be made crumbly again by chopping with a spoon.
  4. Press 2/3 of the crust into the prepared pan, reserving the rest for the topping. Place the topping into the refrigerator.
  5. Bake crust for 10-12 minutes and then set aside to cool. 
  6. When the crust has cooled, pour in the plum jam and spread it evenly over the baked crust.
  7. Sprinkle the remaining crumble topping evenly over the top of the plum jam.
  8. Bake for 25 to 30 minutes, or until the topping is a nice golden brown and the jam filling is bubbling up on the sides.
  9. Let the crumble cool completely on the counter, then in the refrigerator before cutting into squares, at least an hour. You can store this in the refrigerator for 3-4 days or in the freezer for a few months. Be aware that the crust will get softer with time as moisture from the filling soaks into it. 

Notes

I make my own oat flour by whizzing rolled oats in my food processor. For this recipe, I leave them fairly coarse. You could also use all whole oats in the crust, but I like the texture of the mixed oats and flour.

This recipe was inspired by this one.

Keywords: bar cookie, crumble, oat flour, almond flour, coconut flour, fresh plums, homemade plum jam, coconut sugar