Add the fish, spinach and lemon zest, if using, to the pan and season with a little salt and pepper. Bring the milk to a gentle simmer and cook for 3–4 minutes, or until the fish is beginning to ...

You can use any white fish in this gratin recipe, and you can flex your chef muscles over the béarnaise sauce. Gently fry the leeks, carrots and onion in the butter until softened and starting to ...