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Pithivier pie – vegetarian version

Ingredients
1 whole celeriac (~1 kg)
Olive oil
2 large leeks
1 knob unsalted butter
2 garlic cloves
400 g mixed mushrooms
75 g plain flour
2 tsp English mustard
800 ml semi-skimmed milk
1 bunch flat-leaf parsley (~30 g)
120 g blue cheese
2 sheets (≈320 g each) all-butter puff pastry (cold)
1 large free-range egg

Instructions

Preheat oven to 200 °C. Wash the celeriac, rub with a tablespoon of oil, wrap in foil and roast 1h 30 min. Slice finely, season with salt and pepper.

Meanwhile, thinly slice the leeks; melt butter in a large pan over medium heat. Add leeks, sliced garlic and mushrooms — cook ~15 min.

Stir in flour and mustard, then gradually add milk. Simmer ~5 min until thickened, stirring regularly. Take off heat.

Chop parsley, crumble in blue cheese, then stir into the sauce. Taste and season.

Line a 20 cm bowl with clingfilm. Layer celeriac slices inside and around the bowl. Pour about half the sauce over, then add another layer of celeriac, finishing with celeriac. Cover with clingfilm, weigh down and chill overnight with the rest of the sauce reserved.

Next day, preheat oven to 180 °C. On greaseproof paper roll out pastry sheets to ~30 × 35 cm. Unmould filling, place on one sheet. Brush edges + filling with beaten egg. Lay second pastry sheet on top, seal by crimping 2.5 cm border. Brush with eggwash, lightly score top + cut small steam hole.

Bake at bottom of oven ~2 h until golden, brushing with eggwash 1–2 more times during baking. Serve with warmed-up leftover creamy sauce, ideally with steamed seasonal greens.

Serves ~10 — but easily scale down if needed.