Place the flour into a bowl with the salt and the diced butter. Transfer into a food mixer set to a low setting and mix until like fine breadcrumbs – about 1 minute. Alternatively, you could rub the mixture between your thumb and forefinger until it resembles breadcrumbs
Add the egg and then add the iced water, little by little, until the dough comes together (it should not be too dry, otherwise it will just crumble when you roll it out).
Place the dough in cling film and transfer to the fridge to rest for 30 minutes
When the dough is ready to roll out, preheat the oven to 180°C/gas mark 4, and grease and flour your quiche tin. Roll out the pastry to a 0.5cm thickness and lay this into the tin. Line the pastry with a sheet of foil and fill with baking beans
Blind bake the pastry with the baking beans in the oven for 20 minutes, or until the pastry achieves a light golden colour. Remove the baking beans and foil, and brush the base of the tart case with egg yolk.
Bake for a further 5 minutes, then remove from the oven. Allow the pastry to cool while you make the filling
Reduce the oven temperature to 170°C/gas mark 3
Blanch the asparagus in boiling salted water for 3 minutes and then refresh in iced water for two minutes. Drain and dry well
Mix the chervil, chives, mascarpone, spring onion, eggs, egg yolks, salt and pepper in a bowl and set aside
Lay the asparagus spears in the cooled pastry tart, pointing outwards in a circular pattern, then lay the ham in between the asparagus. Pour on the chervil and mascarpone mix
Bake in the oven for 25–30 minutes, until it is light brown and firm to touch in the centre. Allow to cool to room temperature, slice and then serve
Recipe via www.greatbritishchefs.com