1 For the tomato sauce: remove the stalks, then plunge the tomatoes in boiling water for a few seconds. When the skin starts to wrinkle, drain and peel. Remove seeds and dice flesh.
2 Heat the oil in a high-sided frying pan. Add the diced tomatoes, bouquet garni and crushed garlic. Season, cover and gently cook until the tomatoes are soft and tender.
3 Remove the bouquet garni and blend the tomato mixture to form a smooth, frothy sauce. Adjust seasoning to taste.
4 For the gnocchi: heat the milk in a pan, together with a pinch of salt and 100g of butter. When it starts to simmer, remove from the heat, add the flour and stir. Add the rest of the butter, and spirulina. Season. Return to a low heat for 5-6 minutes, stirring regularly.
5 Off the heat, stirring constantly, fold in the grated Parmesan, then the egg yolks one by one. The pasta is ready when it unsticks from the side of the pan to form a smooth, firm and elastic dough.
6 Pour some cold water into a bowl. Dip a teaspoon in the water then use to take a measure of pasta dough. Roll between dampened hands then score with the tines of a fork. Repeat for each gnocchi.
7 Fill a pan with lightly salted water and bring to the boil. Plunge 5-6 gnocchi at a time into the water. Poach for 3-4 minutes until they rise to the surface. Remove with a skimmer and carefully place on kitchen paper.
8 Just before serving, steam heat the gnocchi. Put the tomato sauce in a pan and warm through.
9 Pour a little sauce on a plate or into a dish and place the brilliant green gnocchi on top.