Preheat the oven to 350°F. Grease a 13x9-inch baking dish and set aside. In a large bowl, mix the cubed apples with sugar and ½ teaspoon of cinnamon until well coated. Transfer the apples to the prepared baking dish, spreading them evenly.
5 apples, ½ cup sugar, 1 teaspoon ground cinnamon
In a separate bowl, combine the flour, brown sugar, oats, baking powder, nutmeg, and the remaining ½ teaspoon of cinnamon. Add the cold butter and cut it into the mixture using a pastry cutter or your fingers until it resembles coarse crumbs.
1 cup all-purpose flour, 1 cup brown sugar, ½ cup quick-cooking oats, 1 teaspoon baking powder, ¼ teaspoon ground nutmeg, ½ cup cold butter
Sprinkle the oat mixture evenly over the apples, covering them completely. Bake for 50-60 minutes, or until the apples are tender and the topping is golden brown.
Allow the apple crisp to cool slightly before serving. Enjoy warm on its own or with a scoop of vanilla ice cream.