Method

1. Take the puff pastry out of the fridge and allow to come to room temperature while making the filling
2. Place the butter in wide saucepan and melt over a medium heat. Add the baby leeks and reduce the heat a little, slowly frying the leeks in the butter for 5–6 minutes
3. Add the asparagus and continue to cook for another 10 minutes, stirring occasionally – the aim is to soften and slightly caramelise the vegetables
4. Toss in the garlic right at the end and cook for another minute, then remove the pan from the heat and set aside
5. Meanwhile, bring a small pan of water to the boil and quickly blanch the peas for a minute. Drain and leave to cool until required
6. Once cool, mix the peas with the mascarpone, chopped tarragon and parsley. Finish with a good squeeze of lemon juice and season well with salt and pepper
7. Preheat the oven to 200°C/gas mark 6
8. Divide the puff pastry into 2 and roll out each piece on a lightly floured surface to create 2 circles – a 23cm circle and a slightly larger 25cm circle (you could use large plates as a guide). Place the smaller circle on a baking tray lined with baking parchment
9. Halve the leeks and asparagus and arrange the pieces to form a circle in the centre of the smaller disc, leaving a 2cm border around the edge – try to alternate the pieces to give an even spread
10. Continue stacking the vegetables in overlapping circles until all used up, then mound the pea and mascarpone mixture over the top
11. Brush some of the beaten egg around the pastry border and drape the larger disc of pastry over the top of the vegetables. Press the edges together firmly to seal
12. Decorate the top of the pastry by using a sharp knife to lightly score curved lines outwards from the centre, starting from the top of the pie and curving down to the bottom. Repeat all the way around
13. Brush the remaining egg over the whole dome to glaze and make a small hole in the centre to allow steam to escape
14. Place the baking tray in the oven and bake for 30–35 minutes, until golden and glorious