Prepare the garlic butter by washing the parsley, and chopping it finely. Add to a small bowl with the butter, crushed garlic and lemon juice. Mix with a fork until well combined.

Prepare a roasting tray to be next to you when preparing the next steps. Optionally line it with foil.

Use about a third of the butter to coat the salmon fillets. Season with salt and pepper, and place separately in the centre of the tray. If the fillets have skin on, they are likely to stick if the skin is face down.

Prepare the potatoes by washing them and slicing in half lengthways (so they are long and thin rather than short and thick, this will help them crisp up).

Prepare the asparagus by washing them and slicing off the bottoms.

Coat the asparagus and potatoes with the remaining garlic butter. The easiest way to do this is to get your hands dirty and wash them with hot soapy water at the end.. Use a large mixing bowl, and use your hands to coat all the asparagus with half the remaining butter. Then transfer to the roasting tray. Put all the potatoes in the bowl with the remaining garlic butter, and mix with hands to coat evenly.

Garnish with fresh rosemary and lemon slices on top of the salmon.

Roast for 30-40 minutes at Gas Mark 6/200°C. If the salmon looks like it is drying out when you check on it, baste it (pour some of the butter over it).

Drain any excess butter/salmon juices and serve.