Preheat the oven to 350˚F (177˚C) and spray an approximately 9x13-inch baking dish* with non-stick spray. Melt the vegan butter in the microwave or on the stove and set aside to cool.
½ cup melted vegan butter
Make the fruit filling by combining the apples, cranberries, ⅓ cup brown sugar, oat flour, lemon juice, vanilla extract, and 1 tsp cinnamon in a large bowl. Mix until the apples and cranberries are evenly coated. Spread the mixture in the prepared baking dish.
6-7 cups peeled and chopped apples, 1 cup fresh or frozen cranberries, ⅓ cup brown sugar, 2 tbsp oat flour, 1 tbsp lemon juice, 1 tsp vanilla extract, 1 tsp cinnamon
Make the crisp topping by mixing the rolled oats, oat flour, ⅓ cup brown sugar, ½ tsp cinnamon, nutmeg, and salt in a medium bowl until well combined. Pour in the melted plant-based butter and mix until everything is evenly coated. Use a spoon to evenly distribute the mixture over the fruit in the baking dish.
1 ½ cup rolled oats, 1 cup oat flour, ⅓ cup brown sugar, ½ tsp cinnamon, ¼ tsp nutmeg, ¼ tsp salt
Bake at 350˚F (177˚C) for 50-60 minutes, until the topping is golden brown and the fruit mixture is bubbling. Remove from the oven and let cool for at least 10 minutes before serving.