Set a skillet on medium heat and melt half of the butter.
Clean and chop the leek, then add it to the pan. Sauté for 6-7 minutes on medium heat. Add a sprinkle of salt and white pepper. When soft, transfer the leeks to a bowl and place the skillet back on the stove.
Melt the other half of the butter. Clean and chop the mushrooms and add them to the pan.
Sauté the mushrooms on medium heat for 6-7 minutes, until soft. After a few minutes they will release some water, let evaporate. Remove from the heat and stir in a sprinkle of salt and white pepper.
Crack the egg in a bowl and lightly whisk it with a fork. Stir in the ricotta, a pinch of salt and mix until combined.
Press a shortcrust pastry into a tart pan, prick bottom and sides with a fork and bake in the pre-heated oven at 200°C (390°F) for 10 minutes.
Combine the sautéed leeks, mushrooms and ricotta mixture in a bowl.
Take the shortcrust out of the oven. Add pie filling to the pre-baked shortcrust.
Return the leek mushroom pie to the oven and continue baking for another 25-30 minutes, or until the filling feels set and the sides or the shortcrust have taken a darker tone.
Notes
Unless using a rather small leek, putting 250 g in the savoury pie will leave you with some leftovers. Choose a small leek, make a double batch or just use the white part and save the dark green ends to make stock.Please notice that the nutrition information is only an estimate.