Preheat oven to 350°F and lightly grease a 9x13-inch baking dish.
In a large bowl, toss the sliced apples with ¼ cup sweetener, lemon juice, cinnamon, and nutmeg until evenly coated.
Spread the apple mixture evenly in the prepared baking dish.
In a medium bowl, combine almond flour, chopped nuts, melted butter, ⅓ cup sweetener, and vanilla extract. Mix until crumbly.
Sprinkle the topping evenly over the apples, making sure to cover as much surface area as possible.
Bake for 35-40 minutes, until the apples are tender and bubbling and the topping is golden brown.
Let cool for 10 minutes before serving. This is amazing warm with sugar-free vanilla ice cream or whipped cream!