Preheat the oven to 400ºF / 200ºC degrees and line a baking dish with foil.

Grease the foil and sides of the dish.

Slice the lemon and lay the slices across the bottom of the baking dish. Place the salmon fillet on top.

Whisk together the mustard, honey, olive oil, salt, and pepper, then pour over the salmon.

Bake for around 20 minutes, until the salmon flakes apart easily.

For a charred top, switch the oven to broil and cook for about 5 minutes, until the top is bubbling.

Sprinkle with chopped parsley and serve.