Preheat your oven to 375°F (190°C).

In a large mixing bowl, combine old-fashioned oats, almond flour, brown sweetener, cinnamon, baking powder, and salt. Add cold, unsalted butter and blend until coarse crumbs form.

In another bowl, whisk melted butter, almond flour, lemon juice, unsweetened almond milk, vanilla extract, brown sweetener, and salt until fully combined.

Core and slice medium apples evenly, then coat with the butter mixture.

Grease a 9-inch pie dish, spread the apple mixture, and sprinkle the topping over it.

Bake for 30-35 minutes until topping is golden brown and filling bubbles. Cool slightly before serving.