6 large Granny Smith apples, peeled, cored, and sliced
1/2 cup granulated sugar
1 1/2 tablespoons ground cinnamon
1 teaspoon vanilla extract
1 tablespoon lemon juice
1 cup all-purpose flour
1 cup rolled oats
1 cup brown sugar, firmly packed
1/2 cup cold unsalted butter, cut into small cubes
1/2 teaspoon ground nutmeg
1/4 teaspoon salt
Instructions
Preheat your oven to 375°F (190°C). Lightly grease a 9×9 inch baking dish or a similar-sized ovenproof pie dish with butter or non-stick cooking spray to ensure the apples don’t stick to the sides.
In a large mixing bowl, combine the sliced apples, granulated sugar, one tablespoon of cinnamon, lemon juice, and vanilla extract. Toss everything together until the apples are evenly coated in the sugar and spices. Transfer the mixture into your prepared baking dish and spread them out evenly.
In another bowl, mix the flour, rolled oats, brown sugar, the remaining half tablespoon of cinnamon, nutmeg, and salt. Add the cold, cubed butter. Use your fingers or a pastry cutter to work the butter into the dry ingredients until the mixture resembles coarse crumbs with some pea-sized pieces of butter remaining.
Sprinkle the crumble mixture evenly over the top of the apples. Make sure to cover the fruit completely to create a thick, crunchy crust that will protect the apples as they bake.
Place the dish in the center of the oven and bake for 40 to 45 minutes. You will know it is ready when the topping is a deep golden brown and the apple juices are bubbling up around the edges of the dish. Remove from the oven and let it cool for at least 10 minutes before serving.