Step 1

Heat the oil in a wide, shallow, oven-proof casserole dish *see note 2, over a medium-high heat.

Step 2

Add the chopped sausage and fry for about 5 minutes, stirring regularly, until the sausage is lightly browned (it doesn’t have to be cooked through at this point). Remove from the pan and place on a plate.

Step 3

Add the onion and carrots to the pan and fry for 5 minutes, stirring often, until the onion starts to soften.

Step 4

Add in the salt, pepper, and garlic and stir together.

Step 5

Add the flour, then stir to coat the vegetables.

Step 6

Pour in the chicken stock and add the wholegrain mustard.

Step 7

Add the potatoes and stir together, then bring to the boil and simmer for 10 minutes, until the potatoes are just starting to soften at the edges.

Step 8

Whilst the pie filling is simmering, pre-heat the oven to 200C/400F (fan).

Step 9

After 10 minutes simmering, add the cooked sausages and stir in the cream. Then turn off the heat.

Step 10

Carefully top the casserole dish with the puff pastry. I use two rolls of puff pastry that I squash together. This leaves a bit of a seam down the centre of the pie, but I think that’s fine, since it’s quite a rustic pie.

Step 11

Cut off any really large bits of overhanging pastry, then roll the rest of the overhanging pastry up and back into the pan, to make a rough crust.

Step 12

If you like, you can make a bit of a pastry decoration out of the pastry offcuts (I make a few simple leaves) and place on top of the pie.

Step 13

Pierce the pastry a few times with a sharp knife, to allow steam to escape.

Step 14

Brush the top of the pie all over with the whisked egg (you won’t need all of it).

Step 15

Place the pie in the oven and cook for 20 minutes, until the pastry is golden.

Step 16

Remove from the oven and serve.