This recipe is easily multiplied. I doubled this recipe and it worked just as well.
Preheat oven to 350 degrees. Lightly grease a pie pan or 8-inch square pan.
In a medium bowl, combine sugar, oats, rice flour, 1 teaspoon cinnamon, and coconut oil. Mix until crumbly.
Spread apples in bottom of pie pan. Squeeze lemon juice on top. Sprinkle with 2 tablespoons sugar and 1 teaspoon cinnamon. Top with oat crumble mixture.
Bake for 40 minutes, checking after 25 minutes. Cover with foil if topping is browning too quickly.