Preheat your oven to 375°F (190°C). Lightly grease a 9×9 inch baking dish or a similar-sized casserole dish with butter or non-stick cooking spray to prevent the fruit from sticking.

In a large mixing bowl, toss the sliced apples with the maple syrup, lemon juice, half of the cinnamon, and the nutmeg. Stir until every apple slice is well-coated. Transfer the mixture into your prepared baking dish and spread it out evenly.

In another bowl, combine the oats, flour, brown sugar, salt, and the remaining cinnamon. Add the cold, cubed butter. Use a pastry cutter or your clean fingertips to work the butter into the dry ingredients until the mixture looks like coarse crumbs with some pea-sized bits of butter remaining.

Sprinkle the oat mixture evenly over the top of the apples. Do not press it down too firmly; you want it to remain somewhat loose so it gets extra crispy in the oven. The topping should completely cover the fruit.

Place the dish in the oven and bake for 40 to 45 minutes. The topping should be golden brown and the apple juices should be bubbling around the edges. If the topping browns too quickly, you can loosely cover it with foil for the last 10 minutes.

Remove the crisp from the oven and let it sit for at least 10 to 15 minutes before serving. This cooling period allows the maple-infused juices to thicken into a delicious syrup.