Prepare oven and crust. Preheat the oven to 375°F. Next, put a single pie crust in a pie plate. Then, put a baking sheet lined with aluminum foil on the lower rack to catch any drips.
Make the apple filling. In a large mixing bowl, combine the apples, lemon juice, brown sugar, flour, salt, cinnamon, allspice, and cloves. Mix until the apples are well coated.
Make the crumb topping. To make the mixture, blend the flour and butter until it looks like breadcrumbs. Then, add the brown sugar and oats and gently mix them together.
Assemble the pie. Pour the apple filling into the pie crust. Spread the crumb topping evenly over the apples, making sure it covers everything.
Bake for 50 minutes. Bake the pie for 50 minutes. If the crust edges start to over-brown, cover them with an aluminum foil shield. Allow the pie to cool for at least one hour before serving.