For the pastry, put all the ingredients into a food processor and mix until it forms a dough. Shape the dough into a disc, wrap in cling film and chill in the fridge for at least 2 hours.
Wash the asparagus and trim off the stalky ends. Bring a saucepan with salted water to the boil, add the asparagus and bring back to the boil, then cook for 1 minutes. Drain under cold running water.
After 2 hours, preheat the oven to 180°C fan. Grease a 30cm tart tin.
Roll the dough out thinly on a floured surface and lift into the tart tin. Press against the base and the edges. Prick the base with a fork.
Spread the mustard all over the base and arrange the cooked asparagus all over in a nice pattern.
For the custard, beat the eggs, cream, mayonnaise, parmesan, lemon zest, tarragon, salt and pepper until smooth.
Pour the custard over the asparagus and bake the quiche in the preheated oven for 35 minutes.
This quiche is great served hot or cold.