Once the onion is golden, add the tomato paste, half of the white wine, and the leek (finely chopped). Cook over low heat until the leek is slightly tender, about 5 minutes. Add the thawed and well-drained mixed seafood, the pinch of granulated garlic, the sour cream or crème fraîche, and the remaining white wine. Simmer over low heat, uncovered, for about 20 minutes.

Before filling the pastry shells, check the seasoning. Fill the vol-au-vent shells with the seafood and sauce mixture. Bake the filled vol-au-vent in the oven at 400°F (200°C) for 8 to 10 minutes. Garnish with a peeled shrimp, a wedge of lime, a teaspoon of salmon roe, and a sprig of fresh dill. Serve immediately.