Heat oven to 350°F and lightly grease an 8x8-inch baking dish or 9-inch pie plate.
In a large bowl, toss the apples with the lemon juice, 2 tbsp maple syrup and 1 tsp cinnamon. Spread evenly in the dish.
In the same bowl, stir together the oats, flour, pecans, salt and remaining 1 tsp cinnamon. Add the melted coconut oil and remaining 1 tbsp maple syrup and mix until evenly moist and clumpy.
Scatter the topping over the apples in an even layer and press down very lightly.
Bake 35-40 minutes, until the topping is golden and the apples bubble at the edges. If the top browns too fast, tent with foil for the last 10 minutes.
Cool 10 minutes, then serve warm on its own, with Greek yogurt, or a small scoop of vanilla ice cream.