Place the apples in a large bowl and toss them with the flour, sugar, cinnamon and lemon juice. Fold till they are coated well.
Pour the apples into a greased 9x9in pan or other pan with a similar size (about 2.5 quarts)
Sprinkle the crumble mixture evenly over the apples.
Bake in the preheated oven for 35-45 minutes until the apples are bubbling, and the topping is golden brown and crisp.
Allow to cool for a few minutes then serve warm with ice cream or whipped cream.