Scallops in their shells

Method

1. First, make the white wine sauce. Heat the oil in a heavy-based pan over a medium heat, add the shallot, then gently fry for 5 minutes until really soft but not coloured.
2. Add the fish stock and vermouth, bring to the boil, then simmer for 10-15 minutes until the mixture is reduced by at least half and has a syrupy consistency.
3. Add the cream, then reduce the heat slightly and warm through. Season with salt and pepper, then pass through a strainer or sieve. Stir in the wholegrain mustard and chopped dill, then set aside.
4. Gently remove the scallops from their half shells (they may still be attached underneath – if so, gently cut away with a sharp knife) and separate the white meat from the orange roe. Rinse the scallops and roes, then put them on a plate lined with kitchen towel, then chill. Rinse the shells, pat dry and set aside.
5. Heat the vegetable oil in a frying pan, then add the carrot and leek. Cook over a low heat for 10-15 minutes until soft but not browned. Season, then allow to cool.
6. Preheat the oven to 200°C/fan180°C/gas 6. Take 2 of the washed shells and divide the cooked carrot and leek between them. Cut each of the scallops in half through the middle to form 8 discs, season, then place 4 scallop discs on each shell along with 2 of the roes. Spoon over 2-3tbsp white wine sauce and top with the other cleaned shells.
7. Roll out the pastry on a lightly floured surface into a rectangle, about 8cm x 30cm, and cut in half lengthways. Place a pastry strip around each pair of shells, joining the ends to seal the shells together.
8. Using your fingers, gently press the pastry in place to ensure the seal is tight and there are no holes. Brush the pastry with egg yolk and put the shells on a baking sheet. Cook in the oven for 8-10 minutes until the pastry is golden brown.
9. Remove the shells from the oven and run a sharp knife all the way around the centre of the crusts, so the top shells can be flipped off (as in picture). Serve on a bed of rock salt to hold the shells steady.