Squash, mushroom & chestnut puff pie

Start by preparing the filling. Peel the butternut squash and cut it into small cubes. Steam (or bake) for 20 minutes. If you want to add lentils to the stuffing and are using uncooked lentils, cook them now.

While the squash is cooking, chop the onion into large strips and fry them for a good ten minutes in a pan over a low heat with a drizzle of olive oil, until the onion is melting. Stir from time to time.

Clean the mushrooms and cut them into 4 or 6 quarters depending on their size. Add them to the onions and fry for 4 minutes.

Check if the squash is cooked with the tip of a knife: it should go through the squash easily. As soon as the squash is cooked, add the diced squash to the pan. Crumble the chestnuts and add them to the mixture as well. Add some salt and pepper, nutmeg and mix well and heat on a very low flame. You can add the cooked lentils at this stage.

Meanwhile, prepare a small sauce. Bring the vegetable stock to the boil. Add the cornstarch and stir vigorously with a whisk for 3 minutes. When the mixture starts to thicken and the cornstarch is well dissolved, add the mustard (and possibly the dill and white wine) while continuing to stir with a whisk. Taste the sauce and adjust the seasoning if necessary. Finally, you can add the sourcream if you want to add a creamy touch to the sauce.

Then pour the sauce over the stuffing (in the pan), and stir gently with a wooden spoon to coat the stuffing with the sauce.

Your stuffing is ready! Preheat the oven to 180 °C.

Roll out the puff pastry in a cake tin of about 26/27 cm diameter (or high rim tart tin) covered with baking paper and press the pastry well around the rims so that the pastry is 3 to 5 cm high. Prick the pastry with a fork.

Pour the filling onto the pastry and leave 0.5 to 1 cm of free dough a seam the second pastry.

Beat the egg yolk in a bowl. Brush the free edges with the yolk. Cover the filling with the second puff pastry. Press the edges together well to seal the two pastries. Brush the top of the pie with the yolk.

Make two small holes with the tip of a knife on the top of the pie near the edges.

You can draw patterns on the top of the pie with the tip of a knife. You can also use scraps of pastry to draw patterns (for example leaves, as in the photo) and add these pieces of pastry to the top. Brush with egg yolk as well.

Bake for 30 minutes at 180°C. Keep a close eye on the baking, the pie should be golden brown. Once cooked, remove the pie from the mould and leave to rest on a wire rack for a few moments before eating!