Fish Pie with a Gougère Top: Sauce

Ingredients

  • 300 ml milk
  • a 5 cm strip lemon peel, no pith
  • ½ a Spanish onion, finely sliced
  • 2 blades mace or a large pinch of grated nutmeg
  • 2 cloves
  • 8 black peppercorns
  • 6 parsley stalks
  • 1 bay leaf
  • 37 g butter
  • 1 medium leek, white and pale green part only, finely sliced
  • 37 g plain flour
  • 1 glass dry white wine
  • 2 tbsp double cream (optional) salt
  • 2 tbsp chopped chervil or dill, or 1 tbsp chopped parsley or tarragon

Method

In a small saucepan, heat the milk with the next seven ingredients. Bring very slowly to a simmer and leave to cool. Strain into a jug or bowl, pressing to squeeze out all the liquid. In another saucepan melt the butter and sweat the leek, covered, for 5 minutes. Add the flour and cook gently for a further 5 minutes. Gradually add the strained milk, whisking or stirring hard to avoid lumps, and the wine. Add the cream, and salt to taste, cool, and pour over the fish mixture. Gently stir in the herbs and transfer the lot to an oblong or oval gratin dish, about 25.5cm ∞ 20.5cm. Smooth the top.

Preheat the oven to 400°F/205°C/Gas6.