Preheat the oven to 220 °C. Lightly oil a roasting dish, or line a heavy baking sheet with foil and then add the salmon and season with the tablespoon of lemon juice, pinch of sea salt, and freshly ground black pepper. Roast the Norwegian salmon in the oven until it’s cooked through in the middle. Meanwhile make the sauce by whisking together the yoghurt, 2 teaspoons of lemon juice, dill, and garlic. Drizzle over the salmon and garnish with the remaining dill sprigs to serve.