Step 1

Add the olive oil to a large saucepan on a medium heat. Fry the leeks and garlic for 2 minutes, to soften.

Step 2

Add the mushrooms, herbs, salt and pepper and stir for a minute. Place the lid on top and cook for 8 minutes

Step 3

Meanwhile, in a small saucepan, melt the dairy-free butter on medium heat. Add the flour and stir until combined. Slowly add in the milk, a tablespoon at a time and whisk, until you have a smooth thick mixture. Stir in the nutmeg and season with salt and pepper

Step 4

Combine the cooked leeks and mushrooms with the sauce and leave to cool completely

Step 5

Make sure your puff pastry is at room temperature (if using frozen, leave at room temperature overnight) and preheat the oven to 200C.

Step 6

Add the leek and mushroom mixture to a pie dish and top with the puff pastry, cutting off any excess pastry around the edges.

Step 7

Crimp the edges using a fork and score a criss-cross pattern on the top with a sharp knife. Finally, dip a pastry brush in the aquafaba  (or a little dairy-free milk) and brush the top of the pie, to help it brown, plus secure the edge of the pie crust to the dish.

Step 8

Cook for 25 minutes until golden brown. Serve straight away.