- Put flour and salt in a bowl, and rub in butter with your fingertips until it resembles breadcrumbs. Add water a little at a time, until dough comes together. Wrap in cling film and pop in fridge to chill for around 30minutes.
- Roll out pastry to line a rectangular 36x12 cm tin, or a deep 20cm tin, and leave pastry to overhang slightly.
- Heat oven to 180*fan. Prick base of tart with a fork, line with baking paper and fill with baking beans.
- Blind bake for 15 minutes.
- Remove beans and paper, and cook for 5-10 minutes more until pastry is light golden brown and dry. Trim off overhanging excess with a knife.
For the Filling:
- Melt butter in a frying pan then add sliced leeks and cook until they’re beginning to soften.
- Crack eggs into a jug and whisk in cream. Add salt and pepper and chopped parsley. Add in half the cheese and mix through.
- Scatter the remaining cheese over the base of the tart. Top with cooled leeks, then arrange asparagus and peas on top.
- Pour over cream and egg mixture and bake for 25-30 minutes, until egg mixture is just set.
- Turn tart out onto a plate or serving board, and decorate top with edible pea shoots and pea flowers.