4 large apples, peeled, cored, and sliced
1 cup granulated sugar
1 teaspoon ground cinnamon
1/2 teaspoon ground nutmeg
1 tablespoon lemon juice
1 cup all-purpose flour
1 cup brown sugar, packed
1/2 cup unsalted butter, melted
1/2 cup rolled oats
1/4 teaspoon salt