Preheat the oven to 350°F (180°C) and lightly grease a rectangular baking dish.

Peel and slice the apples into chunky, roughly half-inch pieces. Layer them in the baking dish and drizzle evenly with the maple syrup.

In a large mixing bowl, combine the coconut sugar, gluten-free flour, rice flour, oats, peanut butter, and vegan butter. Work quickly with a fork or pastry cutter until the mixture forms small, even crumbs — avoid overworking it with your hands, or the butter will melt and the topping will clump instead of staying crumbly.

Scatter the crumb topping evenly over the apples, building it up as thick as you like.

Bake for 40-45 minutes, until the topping is golden brown and the apples are fork-tender. Let it rest for 5-10 minutes before serving.

Serve warm, ideally with a scoop of dairy-free vanilla ice cream.