Place the flour and sugar in a roomy bowl and mix well.
Add the cubes of butter, a little at a time and rub into the flour, using your fingertips until the mix resembles breadcrumbs.
Peel & core the apples and cut into 1-2 inch slices and place in a large bowl. The smaller the pieces, the less "whole" they'll be after cooking.
Sprinkle the sugar, flour & cinnamon & mix well.
Butter a rectangular dish (9" x 5" roughly) and spoon the apple mix all over, spreading it out evenly.
Top the apples with the crumble, again evenly, and press down slightly.
Bake in the oven for about 40-45 minutes until the crumble is a golden brown. The fruit seeping out & bubbling is perfectly fine & adds to the beauty of the finish.
Notes
Serve with custard, ice cream, fresh cream or even clotted cream.And when we are having a cocktail and canapé party, I bake the crumble on its own, cook the apples on the stove, let cool then top them in little glasses like these.