Add flour, sugar, rolled oats, salt and half the quantity of cinnamon to a large mixing bowl and combine.
Add butter and then rub ingredients between your fingertips until you arrive at a coarse crumb and then set aside.
Peel and core apples and then slice into 1/4 inch slices.
Layer apple slices at the bottom of your ovenproof dish.
Pour lemon juice over apples evenly and then sprinkle raisins and then the rest of the cinnamon over apples.
Add ginger using grater, just a thin even layer.
Top with crumble mix a cup at a time until apples are thoroughly covered. Lightly press down on crumble to keep in place.
Place in a preheated oven at 375 and cook until apple is tender and crumble is golden brown - approx. 1 hour.
Remove from oven and let cool a little.
Serve while still warm with dulche de leche or vanilla ice cream.