Prep the oven and pan. Heat the oven to 375°F and butter an 8-inch square baking dish.
Prep the apples. Peel the apples and slice them thinly or dice them. Arrange the apples in the baking dish.
Make the topping. In a bowl, combine the brown sugar, flour, oats, cinnamon, nutmeg, and salt. Work the softened butter in with your fingers until well blended and crumbly.
Add the topping to the apples. Sprinkle the crumbs over the apples.
Bake. Transfer the apple crisp to the oven and bake for 30 minutes or until they are tender and the topping is crisp and browned.
Serve. Serve in dessert dishes with ice cream, a dollop of whipped cream, or a drizzle of sweet cream.