1-Preheat the oven at 180C/375F and prepare: Preheat the oven at 180C/375F and prepare the baking dish
2-Peel, core and chop the apples and: Peel, core and chop the apples and transfer into the baking pan. Add flour, sugar, cinnamon, nutmeg, mix to combine then add half the juice of half a lemon and stir to combine
3-In another bowl, combine, oat, flour, brown: In another bowl, combine, oat, flour, brown sugar, cold butter and a pinch of salt, rub with your fingers until you get a breadcrumbs-like consistency. Some chunks are allowed too.
4-Sprinkle the crumble toppings on the prepared: Sprinkle the crumble toppings on the prepared apple fillings
5-Bake in an oven for 35 to: Bake in an oven for 35 to 40 minutes until the topping is crispy, golden and apple filling bubbly.
6-Remove from the oven, stand for a: Remove from the oven, stand for a few minutes and Serve with vanilla ice cream or custard.