Heat oven to 200ºC/400ºF/Gas

Sift flour into a bowl and add salt. Rub in the butter and cream cheese until well incorporated. Add the egg yolk, lemon juice and one teaspoon of iced water and mix to a smooth dough.

Roll out pastry on a lightly floured surface and line a 25.5 cm loose bottomed flan tin. Cut a circle of greaseproof paper to fit the pastry base and weight with dried beans.

Bake for 15 minutes, remove beans and paper and return to oven for a further 5 minutes. Remove and set aside.

Reduce heat to 180ºC/350ºF/Gas 4. Melt the butter in a small pan and cook the onion until soft, stirring frequently. Remove from the heat and leave to cool.

Cut the asparagus spears in half, keeping the spear heads intact, then cut the rest into small rounds. Spread the onion over the hot pastry case, then add the crumbled cheese and the asparagus rounds.

Whisk the eggs and cream together, pour into the pastry case and bake for 15 minutes. Arrange the asparagus spears on top and bake for a further 25-30 minutes until set.