Heat the olive oil, add the diced shallot and the peeled, finely chopped cloves of garlic and fry until golden. Dice the tomatoes, add them and cook for a few minutes. Put in the prepared prawns, braise briefly, pour in white wine and water and simmer until the brew has thickened. Season with salt, pepper and piri piri or cayenne pepper.
Boil the spaghetti in salted water, pour on a sieve, drain, arrange on preheated plates, put a few flakes of butter on top and pour the shrimp sauce over it.