Step 1

Heat the butter and oil in a heavy-based pan, add the leeks, carrot, celery, garlic and thyme and cook for 2 minutes until starting to soften.

Step 2

Add the chicken and cook gently without colouring for up to 10 minutes. Stir in the flour and cook for 1 minute.

Step 3

Pour in the wine and stir continuously, making sure that the wine reduces and the sauce thickens. Pour in the chicken stock one-third at a time, stirring continuously and making sure the sauce is thick and smooth before adding the next batch.

Step 4

Add the bay leaf, cover the pan and cook gently for 1 hour.

Step 5

Stir in the mustards, cream and freshly grated nutmeg to taste. Add salt if needed.

Step 6

Preheat the oven to 180 ̊C (350 ̊F) Gas 4.

Step 7

Meanwhile, bring a large pot of water to the boil, add the thinly sliced potatoes and boil for 12 minutes, take off the heat and drain well. Spread them out in a layer to allow the excess water to evaporate off.

Step 8

Place the chicken mixture into a pie dish 24cm in diameter and carefully lay the potatoes on top of the filling, overlapping them slightly, like a pie top.

Step 9

Brush the potatoes with a little melted butter, season with salt and pepper and top with the thyme. Cook in the preheated oven for about 50 minutes. The pie is ready once the potatoes are cooked and golden brown.

Step 10

Serves: 6