For the Filling:
6-8 McIntosh or Honeycrisp apples, peeled, cored, and thinly sliced
1/2 cup granulated sugar
1 tablespoon lemon juice
1 teaspoon ground cinnamon
1/4 teaspoon ground nutmeg
1 tablespoon all-purpose flour
For the Crisp Topping:
1 cup old-fashioned oats
1/2 cup all-purpose flour
1/2 cup brown sugar, packed
1/2 teaspoon ground cinnamon
1/4 teaspoon salt
1/2 cup (1 stick) unsalted butter, melted
Preheat the Oven: Preheat your oven to 375°F (190°C). Grease a 9x9-inch baking dish or a similar-sized oven-safe dish.
Prepare the Apple Filling: In a large bowl, combine the sliced McIntosh apples, granulated sugar, lemon juice, ground cinnamon, ground nutmeg, and all-purpose flour. Toss until the apples are evenly coated. Transfer the apple mixture to the prepared baking dish and spread it out evenly.
Make the Crisp Topping: In another bowl, mix together oats, all-purpose flour, brown sugar, ground cinnamon, and salt. Add the melted butter and mix until everything is
combined and the mixture is crumbly.
Top the Apples: Spread the crisp topping evenly over the McIntosh apple mixture, covering it entirely.
Bake: Place the baking dish in the preheated oven and bake for about 30-35 minutes or until the topping is golden brown and the apple filling is bubbling.
Serve: Remove from the oven and let it cool slightly. Serve warm on its own or with a scoop of vanilla ice cream.