Preheat oven to 220°C/430°F (200°C fan). Line a tray with parchment/baking paper.

Trim fins: Cut all fins off the fish using scissors – both fins on the side, and the fins on the back and underside of the fish (but not the tail).

Slash flesh: Cut 3 slashes on each side of the fish, cutting through flesh down to the bone (see photos in post and/or video, helpful!).

Stuff fish (Note 2): Sprinkle a bit of salt and pepper inside the cavity of the fish. Scatter the cavity with garlic slices, then stuff with parsley and dill. Layer lemons on top of herbs.

Tie fish (Note 3): Using kitchen string make 3 ties to hold fish together.

Season skin: Sprinkle remaining salt and pepper on the skin (both sides), including a bit on the head of the fish. Then drizzle with olive oil. Rub all over the fish, including in the slashes.

Bake 20 minutes (Note 4): Place fish on prepared tray. Bake for 20 minutes or until the internal temperature is 55°C/131°F (insert thermometer in the thickest part of the fish, not against the bone). Alternatively, use a small knife at one of the cut slits in the fish to prise a bit of meat gently away from the spine. If it flakes away from the bone without resistance, it's done.

Rest: Remove from oven, transfer to serving platter and leave it to rest for 5 minutes. The internal temperature will rise to 58°C / 136.5F ("medium", ie. just-cooked and not raw at all, very juicy and moist).

Serve with Garlic & Dill Butter Sauce on the side. Either pour over the butter just prior to serving the fish, or let everyone help themselves. See this video by Serious Eats for a concise tutorial for how to carve and serve a whole roasted fish.

Melted butter: Place butter in a saucepan over medium-high heat. Once melted, add garlic and cook, stirring, for 45 seconds to 1 minute until it smells ridiculously good and you're salivating!

Add dill: Remove from heat. Stir in dill. Use per recipe.