This leek and mushroom pie with potatoes is not only deliciously comforting and satisfying but also healthy. It’s full of flavour, brimming with vegetables, low in fat and comes with a light and crispy puff pastry topping.
Boil the potatoes in salted water with a bay leaf until fully cooked but still firm. Drain well and place in the bottom of your pie dish. While the potatoes are boiling make the filling.
Rinse the porcini mushrooms rubbing gently with your fingertips to remove any grit, then place in a small bowl and add a little water just to cover the porcini (about 4 tablespoons). Leave to soak while you prepare the other ingredients.
In a frying pan heat up 2 tablespoons of oil and fry the leeks slowly over a low-medium heat for about 10 minutes until softened but not browned, stirring often. Season to taste and transfer into a bowl. Preheat the oven to 400 F/ 200 C/ gas mark 6.
In the same pan heat up 2 more tablespoons of oil and fry the chopped mushrooms over a fairly high heat for about 6 minutes until they reduce in volume and release water.
Chop up the porcini and add into the pan (along with the water they soaked in). Add the leeks, parsley (if using), corn flour, onion granules and fromage frais. Stir and continue cooking until the mixture thickens. Add in the water, stir, season generously and remove from the heat. Pour the mixture over the potatoes.
Place your pastry sheet over the top and trim to fit your dish gently sealing along the edges and removing any air pockets. Make a little cut in the centre to allow excess steam to escape and brush the pastry with the egg wash.
Bake in the centre of the oven for 30 minutes or until golden brown. If the pastry starts to brown too much after 20 minutes cover it loosely with parchment paper or foil. Remove from the oven, rest for 5 minutes then serve.
Make ahead: You can boil the potatoes in advance and once cooled refrigerate until you are ready to make the recipe. Also once you’ve assembled the pie you can refrigerate it overnight and bake the following day (ensure the pie filling has had time to cool down before covering it with the pastry).
Substitutions: I used fresh parsley but you could swap that for a bit of thyme (1.5 tsp) or not use any herbs at all. I also used naturally low in fat fromage frais, but you can use crème fraiche instead if you prefer (though keep in mind it’s much more calorific).
Baking: If the pastry starts to brown too much after 20 minutes in the oven, cover it loosely with baking paper or foil.
Best served immediately while the pastry is hot and crispy.
Freeze it: Freeze the pie, uncooked, covered, for up to 3 months. Bake from frozen (do not freeze the pie if you’ve used previously frozen pastry to make it).