• Position a rack in the lower third of the oven and preheat the oven to 350ºF.
• Peel and core the apples. Cut into thin slices, about ?-inch thick.
• In a large bowl combine the apples, apple cider, maple syrup, lemon juice, apple pie spice, and salt. Stir to coat.
• Spread the apples into a 9-inch round baking dish with 2-inch high sides or an 8x8-inch square pan. Dot with cubed butter.
• Bake until bubbling, about 30–35 minutes. Stir gently.

For the crumble topping

• While the apples bake, prepare the topping. In a bowl, combine almond flour, coconut flour, nuts, coconut sugar, apple pie spice, and salt.
• Stir in the melted butter until the mixture resembles coarse crumbs.
• Crumble topping evenly over the partially baked apples.
• Return to the oven and bake until the topping is deep golden and the apples are bubbling, 40–50 minutes (check after 25 minutes, as ovens vary).
• Let cool for at least 10 minutes before serving. The topping will crisp as it cools.