Cep Custard Tart with Parmesan Foam

⏱ 150 min · Serves 6

A silky baked porcini custard in a crisp, thyme-scented pastry shell, crowned with a cloud of airy Parmesan foam and a scatter of caramelised mushrooms. Deeply savoury, faintly sweet with cream and cep, this is the sort of thing that makes a table go quiet for a moment.

Per serving: 702 kcal · 20.0g protein · 33.0g carbs · 54.0g fat

Ingredients

• For the pastry:
• 200g plain flour
• 120g cold unsalted butter, cubed
• 1 egg yolk
• 1 tsp thyme leaves
• 2-3 tbsp ice water
• 1/2 tsp fine salt
• 1 egg white, beaten (for sealing)
• For the cep custard:
• 25g dried porcini (cep) mushrooms
• 200ml boiling water
• 200g fresh chestnut or fresh cep mushrooms, sliced
• 2 tbsp unsalted butter
• 1 shallot, finely chopped
• 1 garlic clove, minced
• 1 tbsp dry Madeira or dry sherry
• 250ml double cream
• 100ml whole milk
• 3 whole eggs + 1 yolk
• 30g finely grated Parmesan
• Pinch of grated nutmeg
• Salt and white pepper
• For the Parmesan foam:
• 250ml whole milk
• 100ml double cream
• 80g Parmesan, finely grated
• 1 small garlic clove, bruised
• 1/2 tsp soy lecithin (optional, for a sturdier foam)
• To finish:
• 100g mixed mushrooms, torn
• 1 tbsp butter
• Chives or micro herbs
• Truffle oil (a few drops, optional)

Method

1. Make the pastry: rub or pulse butter into flour and salt until sandy. Add thyme, egg yolk and just enough ice water to bring it together. Flatten to a disc, wrap and chill 45 minutes.
2. Roll out to 3mm and line a 23cm loose-bottomed tart tin, leaving overhang. Chill 20 minutes, then blind bake at 180C fan with baking beans for 20 minutes. Remove beans, brush inside with egg white and bake 8 minutes more until dry and golden. Trim the overhang.
3. Soak the dried ceps in the boiling water for 20 minutes. Lift out, chop finely, and strain the soaking liquid through muslin; reduce it in a small pan to about 3 tbsp of intense mushroom essence.
4. Melt butter in a frying pan, cook the fresh mushrooms hard until browned and squeaky-dry. Add shallot and garlic, soften 2 minutes, add chopped ceps and Madeira and cook off. Stir in the reduced cep essence, season, and cool slightly.
5. Blitz two-thirds of the mushroom mixture with the cream and milk until smooth, then whisk in eggs, extra yolk, Parmesan and nutmeg. Season well with salt and white pepper and pass through a fine sieve.
6. Scatter the remaining mushroom mixture over the tart base, set the case on a tray, and pour in the custard. Bake at 130C fan for 30-35 minutes, until set with the faintest wobble at the centre. Cool 20 minutes before slicing.
7. For the foam: warm milk, cream and garlic to a bare simmer, off the heat whisk in the Parmesan until melted, strain, and season. Whisk in lecithin if using. Keep warm.
8. Fry the mixed mushrooms in butter until golden and crisp at the edges; season.
9. Froth the Parmesan liquid with a stick blender tilted at the surface until a thick foam builds. Serve each slice warm topped with fried mushrooms, a generous spoon of foam, chives, and a whisper of truffle oil.