Preheat the oven to 180C/350F. Core and cut the apples in pieces. In a saucepan caramelize the apples with the lemon juice, the brown sugar, the cinnamoon and some of the plain flour. Cook for 5/7 minutes, or until the apples have softened.
Cube the butter and place in a large plate/mixing bowl with the flour. Rub together with your fingertips until it resembles breadcrumbs, then scrunch in the remaining sugar to add a little texture.
Bake in the oven for 40-45 minutes until the crumble is browned and the fruit mixture bubbling. Serve with crunchy pomegranate seeds and decorate with rosemary on top.