To make the pastry, put the flour, butter and cheese into a food processor. Whizz until it looks like breadcrumbs. Add the egg and water and whiz until the mixture forms a ball.
Roll out on a lightly floured work surface and line the base and sides of the flan tin with the pastry. Set aside to chill in the fridge for 30-35 minutes. Prick the base and line with baking beans.
Pre-heat the oven to 220C / 200C Fan / Gas mark 7. Blind bake the pastry for 10 minutes. Remove the beans and bake for another 8-10 minutes until lightly golden. Place on a baking sheet.