1. To make the pastry, mix the flour and icing sugar together in a bowl. Add the diced butter and rub it in with your fingertips until the mixture looks like fine breadcrumbs. Mix the egg with the lemon juice and water. Make a well in the centre of the flour mixture and pour in the egg mix. Using one hand, work the liquid into the flour to bring the pastry together. If it’s a little too dry, add a splash more water. When the dough begins to stick together, gently knead into a ball. Wrap in cling

2. Turn out the dough on to a lightly floured work surface and roll it out into a circle that’s about 3mm thick. Press the pastry into the base and sides of a 25cm loose bottom tart tin and leave the excess pastry hanging over the edge. Prick the base all over with a fork, then chill in the fridge for 15 minutes.

. Preheat the oven to 200°C/Gas 6. Line the chilled pastry case with parchment paper and baking beans.

Bake the pastry case in the oven for 12 to 15 minutes, or until the edge of the pastry is light golden brown. Remove the baking beans and paper, and bake for a further 5 to 8 minutes, or until the pastry case is crisp and golden brown all over. Once cooled, carefully trim the edge to remove any overhanging pastry and to neaten the edge.

For the filling, place the apple, sugar and water in a large, deep saucepan and cook over a medium heat for 5 minutes, stirring occasionally. Cover the pan with the lid and bring the mixture to a gentle simmer. Cook gently until the apple has softened but not collapsed. Set aside to cool.

To make the crumble, mix the flour, oats and brown sugar together in a large bowl, then stir in the melted butter until the mixture forms large crumbs.

Sprinkle the semolina across the base of the cooked tart – this helps to mop up any juice from the apple and prevents the base going soggy. Spread the cooled apple filling into the case. Sprinkle the crumble topping all over the apple filling and bake the tart at 200C/180C Fan/Gas 6 for 20 to 25 minutes, or until the crumble is crisp and golden brown.

Serve the tart warm, in slices, with pouring cream or custard.