Step 1

In a large bowl, combine the flours, cubed vegan margarine, salt and cayenne pepper (if using). Use your fingertips to rub the fat into the flours until the mixture resembles breadcrumbs.

Step 2

Add just a splash of dairy-free milk at a time until the mixture comes together to form a soft dough. If it becomes too sticky, add a little more flour.

Step 3

Roll out the dough on a floured surface. Grease or spray with oil a loose-bottomed pie dish or tart tin (about 23cm), and line the tin with pastry. Leave a little pastry overhanging the edges to avoid shrinkage, (you will slice it off after cooking). Chill the pastry case until needed later.

Step 4

Preheat the oven to 180ºC/350ºF/Gas Mark 4.

Step 5

Peel the potatoes and cut them into cubes of 1-2cm. Boil for 4-5 minute until just starting to soften, then drain and set aside.

Step 6

Meanwhile, trim and slice the leek and onions. Heat the oil in a large pan and fry gently for 8-10 minutes until soft.

Step 7

Trim and slice the spring onions, remove the thyme leaves from their stalks, and finely chop the parsley.

Step 8

Combine all the filling ingredients and mix together. Season well with salt and black pepper.

Step 9

Tip the filling into the pastry case and level it out, pushing right to the edges so it is evenly spread.

Step 10

Place your pie on a baking tray and bake in the oven for 40-45 minutes until deeply golden. Trim excess pastry from the edges with a sharp knife, then remove from the tin and serve.