Preheat your oven to 350°F (175°C) and lightly grease an 8x8-inch baking dish or similar-sized oven-safe dish.

In a large mixing bowl, combine the sliced peaches, lemon juice, maple syrup, vanilla extract, 1 teaspoon cinnamon, nutmeg, and cornstarch. Mix until the peaches are well coated. Set aside.

In another mixing bowl, prepare the crumble topping by combining the rolled oats, almond flour, chopped nuts (if using), coconut sugar, melted coconut oil, 1/2 teaspoon cinnamon, and a pinch of salt. Stir until the mixture is crumbly and evenly coated.

Transfer the peach mixture to the prepared baking dish, spreading it out evenly.

Sprinkle the crumble topping evenly over the peaches, ensuring they are fully covered.

Bake in the preheated oven for 30-35 minutes, or until the topping is golden brown and the peach filling is bubbly.

Allow the crumble to cool for 10-15 minutes before serving. Enjoy warm, optionally topped with a dollop of Greek yogurt or a scoop of vanilla ice cream for added indulgence.