These gluten-free, vegan plum-oatmeal crumble bars have a delicious oatmeal-almond crust and crumble topping. The slightly sweet, cinnamony crust makes a great flavor contrast with the tartness of the simple homemade plum jam filling.
And whether or not you offer them as a Christmas treat or Thanksgiving dessert, they are pretty and just mildly sweet. And of course, gluten-free and vegan.
I love fresh plums but I always go a little crazy at the farmer’s market and buy too many to eat fresh. These crumble bars are in-between my plum-peach cobbler and a firm cookie. You can top them with coconut yogurt as I did with the cobbler, or not!
They make a good potluck addition except, of course, they are not nut-free. Recently a group I’m in that meets regularly has been asked not to include any nuts in our snacks. So I hope to work on nut-free options for recipes like this one.
What’s the difference between a crumble and a cobbler?
A cobbler has the crust on the top only, and the crust is usually moist enough to drop onto the fruit in spoonfuls. A crumble has part of the crust on the bottom, which is pre-baked, and part crumbled (hee, hee) and sprinkled on top of the filling.
Stages in making the crumble bars
The thicker your plum jam, the firmer and more cookie-like your bars will be. It should mound up on the spoon. If not, keep cooking it. In the photo below, it was close, but I had time and cooked it a bit longer.
When you have stirred the crust together, it should be (no surprise) crumbly rather than loose or sticky. You should be able to press a portion of it into the parchment-lined pan without it falling apart.
The crust is slightly browned after baking and becomes firm enough to spread the plum jam on top. After baking the crumble, the top is browned and some of the filling bubbles up on the edges.
Let it cool on a rack, then refrigerate for at least an hour before cutting into bars.
Additional Recipe tips
If your plums are sweet, rather than tart, consider adding a tablespoonful of lemon juice to the filling.
Cooking times are approximate, because a lot depends on how moist your plums are. If they are very ripe and soft, it may take longer to cook that extra moisture out of them than I’ve indicated here.
If you want a thicker filling, you can also add another tablespoonful of tapioca. A few people say there is a noticeable texture when you add more tapioca, but most can’t detect the extra.
I always reduce the amount of sugar called for in a recipe, and these are a good match for my less-sweet preference. For a sweeter bar, you can either add another tablespoon or so of coconut sugar, or sprinkle sugar on top of the bars for a slight sparkle.
These bars can be “dressed up” for a Christmas gathering, as I’ve done, or could make a beautiful Valentine’s dessert because the plum filling turns out such a beautiful red. Or you can serve them any time that you have fresh plums.
If you make this recipe, please leave me a note in the comments so that I know how it went!
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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.
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)
- 4–5 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
- 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
- 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).
- 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
- While the plum mixture is cooking, stir the almond flour, gluten-free rolled oats, oat flour, coconut flour, and cinnamon/nutmeg together in a mixing bowl.
- 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.
- 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.
- Press 2/3 of the crust into the prepared pan, reserving the rest for the topping. Place the topping into the refrigerator.
- Bake crust for 10-12 minutes and then set aside to cool.
- When the crust has cooled, pour in the plum jam and spread it evenly over the baked crust.
- Sprinkle the remaining crumble topping evenly over the top of the plum jam.
- 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.
- 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.
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
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