Boil 1.5 cups of water and add salt to taste. When the water starts to boil add the rice and stir. Cover the casserole dish and allow it to simmer for between 15 and 20 minutes or until the rice has softened and all the water has been absorbed. Remove the rice from the heat and, while stirring, , add the egg white and a soup spoonful of garlic. Press the rice into the bottom of a square mould covered with butter.

Melt the butter in an anti-stick frying pan between medium and high heat. Add the garlic, mushrooms and celery. Stir on the heat for a further 5 minutes. Add the spring onions, salt, ¼ teaspoonful of pepper coffee and the two spoonfuls of Jumbo Gamba. Cook on a high heat for about two minutes, stirring. Set the greens aside in a large bowl. Dry this same pan with a cloth or absorbent paper, add the rest of the water and wait until it starts to boil. Add the shrimps, cook them for 1 minute or until they turn pink. Set a cup of the liquid from the cooking aside.

Wash the shrimps in cold water, peel them and place them on the rice. Melt the rest of the butter in pan at medium heat. Add the flour and mix it. Simmer for 2 minutes, stirring. Add the milk and the liquid from the cooking and mix with a stirrer. Simmer by stirring for about 20 minutes or until the sauce thickens.

Remove from the heat, add the Gruyere, the grated lemon, the rest of the salt and the pepper. Simmer until it is reduced to a homogeneous sauce. Add this sauce and the rest of the parsley to the greens and mix. Pour it over the shrimps. Mix the rest of the Gruyere with the breadcrumbs in a small bowl. Spread it over the preparation with the shrimps. Put it in the oven at 325º for 45 minutes. Cook au gratin until it is golden brown (about two minutes).