Preheat the oven to 375f.
Place the pastry into the pie dish.
Roll out the almond paste and lay into the base of the pie crust.
Place in the fridge whilst you prepare the rest of the ingredients
Combine the flour, oats, pecans, light brown sugar and half a teaspoon of cinnamon in a bowl. Add in the cold butter cubes and using a cutter or your fingers work the butter into the mixture until you have a crumb like consistency.
In a separate bowl mix together the white sugar and remaining half teaspoon of cinnamon.
Toss the apple into the cinnamon sugar to coat all sides.
Place the coated apples into the pie shell then cover with the crumble topping.
Bake in the oven for 50 minutes until the apples are soft and the topping golden.
Serve with hot custard or a scoop of vanilla ice cream.