Season the Atlantic salmon with salt and pepper.

Cut the new onion into 1cm thick rings (3 slices) and finely chop the rest. Soak the chopped onion in water, then drain and pat dry.

Trim the asparagus, peel the lower third, and cut into 5mm cubes. Microwave the asparagus in a heatproof container for 1 minute at 600W, then let cool.

Mash the boiled egg in a bowl, then mix with mayonnaise, salt and pepper, chopped onion, and asparagus to create the spring vegetable tartar sauce.

Heat half the salad oil in a pan over medium-low heat. Cook the onion rings for 3–4 minutes, flipping occasionally, until tender. Remove from the pan.

Add the remaining salad oil to the pan and sear the salmon on high heat until browned on all sides. Let cool slightly, then cut into bite-sized pieces.