Preheat the oven and prepare the dish: Set your oven to 190°C (fan-assisted). Lightly butter the inside of your baking dish — this prevents sticking and adds a subtle richness to the bottom of the sauce. You should see the butter melt and coat the dish evenly as you work.

Season the salmon fillets: Pat the salmon dry with kitchen paper. Season both sides generously with salt and pepper. The surface should feel dry to the touch, which helps the seasoning adhere and ensures the sauce clings properly.

Make the creamy sauce: In a medium bowl, whisk together the double cream, chicken stock, minced garlic, Dijon mustard, grated Parmesan, dried dill, lemon zest, and lemon juice. The mixture should look smooth and pale yellow, with the mustard and cheese fully incorporated — you should smell the garlic and lemon immediately.

Assemble the dish: Arrange the salmon fillets in a single layer in the prepared baking dish, leaving a small gap between each piece. Pour the creamy sauce evenly over and around the fillets. Gently tilt the dish so the sauce settles in an even layer; you should see the tops of the salmon just peeking through the sauce.

Bake the salmon: Place the dish in the preheated oven and bake for 20-25 minutes. The sauce should be bubbling gently around the edges, and the top of the salmon will turn opaque with a slight golden hue. The flesh should flake easily when tested with a fork — if it resists, give it another 2-3 minutes.

Rest and garnish: Remove the dish from the oven and let it rest for 5 minutes. During this time, the sauce will thicken slightly as it cools. Sprinkle with fresh parsley and a final grating of lemon zest. The contrast of bright green and yellow against the creamy sauce is what makes this dish truly restaurant-worthy.