Vegetarian Mushroom and Ale Pie

Place the dried porcini mushrooms in a heatproof bowl, pour over the boiling water, and set aside to rehydrate for 20 minutes. Once softened, lift out the mushrooms and roughly chop them. Pour the soaking liquid through a fine sieve lined with kitchen paper, reserving the liquid and discarding any grit.

Dice and prep all vegetables, mince the garlic, pick and chop the herbs, and measure out all remaining ingredients before you begin cooking.

Melt 2 tbsp of the butter with the olive oil in a large, heavy-based casserole or Dutch oven over high heat. Add the fresh mushrooms in a single layer — work in two batches to avoid crowding — and cook undisturbed for 3–4 minutes until deeply golden on one side, then toss and cook for a further 2 minutes. Season with salt and transfer to a bowl.

Reduce the heat to medium and add the remaining 1 tbsp butter to the same pan. Add the onion, carrot, and celery and cook, stirring occasionally, for 8–10 minutes until softened and beginning to colour at the edges.

Add the garlic, thyme, rosemary, and tomato paste and cook, stirring constantly, for 2 minutes until the tomato paste darkens slightly and smells fragrant.

Scatter the flour over the vegetables and stir vigorously for 1–2 minutes to cook out the raw flour taste.

Pour in the ale slowly, scraping up any browned bits from the base of the pan, and stir until smooth. Add the reserved porcini soaking liquid, vegetable stock, Worcestershire sauce, Marmite, and Dijon mustard. Stir to combine.

Return the sautéed fresh mushrooms and the chopped rehydrated porcini to the pan. Bring to a gentle simmer over medium heat and cook, uncovered, for 20–25 minutes until the gravy has thickened enough to coat the back of a spoon generously. Taste and adjust seasoning. Transfer the filling to a 23–25 cm deep pie dish and leave to cool completely.

Leave the filling to cool to room temperature, then refrigerate until fully cold, at least 1 hour.

Preheat the oven to 200°C (180°C fan / Gas 6). On a lightly floured surface, roll out the pastry to approximately 3–4 mm thickness and a size roughly 4 cm larger than your pie dish. Drape the pastry over a rolling pin and lay it over the cold filling. Press the edges firmly onto the rim of the dish, trim any excess, and crimp with a fork or your fingers. Cut two small steam vents in the centre with a sharp knife.

Brush the pastry lid all over with the beaten egg wash and place the pie on a baking tray. Bake in the preheated oven for 35–40 minutes until the pastry is a deep golden brown and the filling is bubbling through the vents.

Remove from the oven and rest for 5 minutes before serving.