You can prepare the crumble topping in advance and keep it in the refrigerator until ready to use.

In a bowl or using a food processor, combine the flour, sugar, butter, and cinnamon until the mixture has a sandy, crumbly texture. If working by hand, use your fingertips to rub the ingredients together until it resembles coarse crumbs.

You can prepare the crumble topping in advance and store it in the refrigerator until you're ready to use it.

Butter two small gratin dishes or one large dish. If using six apples, you'll need three small gratin dishes.

Peel the apples, remove the core and seeds, and cut them into large chunks directly in the dishes.

Top the apples with a generous layer of crumble, breaking it up with your fingertips to create a crumbly texture.

Crumble the rest of the crumble topping onto a baking sheet and bake it separately until golden brown.

Once the apple crumble and the separately baked crumble topping are done, remove them from the oven and let them cool slightly on a wire rack.

Sprinkle the crumble with the crispy topping, creating a generous layer.

Serve warm or cold, optionally with a scoop of vanilla ice cream or a dollop of cream for extra indulgence.