3 large apples, peeled, cored, and diced into 1/2-inch pieces
2 tablespoons apple juice
1/4 cup granulated sugar
1/2 teaspoon salt
1 1/2 teaspoons ground cinnamon, divided
1 tablespoon all-purpose GF flour
1 1/4 cups gluten-free rolled oats
2 tablespoons melted butter
2 tablespoons brown sugar
4 tablespoons room-temperature butter
Preheat the oven to 375F. Grease an 8×8 baking dish.
In a large bowl, combine the plums, apples, and apple juice. Add the sugar, salt, 1 teaspoon of the cinnamon, and the flour. Once these are combined, add the oats and the melted butter. Toss to combine well.
Transfer the mixture to the baking dish.
In a small bowl, combine the remaining 1/2 teaspoon of the cinnamon, the brown sugar, and the room-temperature butter, and mix until the butter is broken down into small balls.
Distribute the butter crumbles over the oat and fruit mixture.
Bake for 50 to 60 minutes, until the oats are golden brown and the apples are tender.