Mushroom and Ale Pie

Ingredients

Equipment Needed

• •Large heavy-based frying pan or wide casserole
• •1.5-litre ovenproof baking dish
• •Pastry brush

Instructions

1. 1

   Cook the onions down

   Melt half the butter with the oil in a large pan over a medium heat. Add the onions and a pinch of salt. Let them cook slowly, stirring now and then, until they've softened and turned sweet and slightly golden. This takes a good ten minutes. Don't rush it. The onions are the foundation, and a rushed foundation shows.

   A wide, heavy pan is worth reaching for here. The mushrooms need room. Crowded mushrooms stew rather than fry, and stewed mushrooms are a sad, grey affair.
2. 2

   Fry the mushrooms

   Push the onions to the side and add the remaining butter. When it foams, add the mushrooms. Leave them alone for a minute or two. You want proper colour on them, deep golden edges, not pallid and steamed. They'll release their liquid first. Let it cook away entirely until the pan is dry and the mushrooms are starting to catch and caramelise. Now add the garlic, thyme sprigs, and bay leaf. Stir everything together and cook for another minute until the garlic smells warm and sweet.

3. 3

   Build the sauce

   Scatter the flour over the mushrooms and stir it through for a minute so it loses its raw taste. Pour in the ale. It will bubble up and hiss. Good. Stir well, scraping up anything stuck to the bottom of the pan, because that's where the flavour lives. Add the stock, the tomato purée, and the mustard. Bring it to a gentle simmer and let it cook for ten to fifteen minutes until the sauce has thickened to something rich and glossy that coats the back of a spoon. Season well. Taste it. Then taste it again. It should be deep, savoury, and slightly bitter from the ale. Take the pan off the heat, fish out the thyme stalks and the bay leaf, and let the filling cool while you deal with the oven.

   The filling needs to cool a little before the pastry goes on. Hot filling melts the butter in puff pastry before the oven can set it, and you'll lose the rise. Ten minutes is enough.
4. 4

   Top with pastry

   Set the oven to 200C/180C fan. Tip the filling into a baking dish, roughly 1.5 litres, and spread it out evenly. Lay the puff pastry sheet over the top, trimming it to fit with an overhang of a centimetre or so. Press the edges gently against the rim of the dish. Cut two or three slits in the top to let the steam escape. Brush the pastry with beaten egg. Be generous. The egg is what gives you that deep, lacquered gold.

5. 5

   Bake until golden

   Bake for twenty-five to thirty minutes, until the pastry has puffed up proud and gone a deep, burnished gold, and you can see the filling bubbling through the slits. Let it sit for five minutes before you bring it to the table. Serve it straight from the dish with a spoon, not a knife. This isn't a neat pie. It's a generous one.

Chef Tips

• •Use a mix of mushrooms. Chestnut mushrooms hold their shape and have a good, nutty bite. Large flat mushrooms or portobellos torn into pieces give you the dark, meaty quality the pie needs. All one type is fine, but a mixture is better.
• •Choose an ale you'd drink. A good bitter, a brown ale, a porter. Something with malt and depth, not hops and citrus. The ale reduces and concentrates, so anything you don't like in the glass, you'll like even less in the pie.
• •Don't apologise for shop-bought puff pastry. The honest truth is that good all-butter puff pastry from the supermarket is better than anything most of us will make at home on a weeknight. Life is short. Use the pastry. Make the filling properly. Your kitchen, your rules.
• •If you have half a teaspoon of Marmite in the cupboard, stir it into the sauce with the stock. It dissolves into the background and adds a quiet, savoury depth that you can't identify but you'd miss if it weren't there.

Advance Preparation

• •The mushroom filling can be made a day ahead and refrigerated. If anything, it improves. Reheat it gently before topping with pastry and baking.
• •You can assemble the whole pie, pastry and all, and refrigerate it for up to six hours before baking. Add five minutes to the oven time if baking from cold.
• •Leftover filling, without the pastry, keeps for three days in the fridge and reheats well. Good on toast, spooned over a baked potato, or stirred through pasta if you need a quick second life for it.

Frequently Asked Questions

Nutrition Information

1 serving (about 370g)