Coarsely dice the onions and braise them in the butter in a large pot over low heat, covered, for about 20 minutes. The onions should not brown, just become soft. Add the diced tomatoes and braise for another 5 minutes. Dust with flour and sweat briefly.
Deglaze with the stock, bring to the boil and simmer gently for 15 minutes. For the beurre noisette, heat butter in a small saucepan until it turns brown and begins to smell of nuts.
Then immediately stop the roasting process by placing the pan in cold water. Add the coarsely chopped basil to the soup and puree the soup with a magic wand. Add beurre noisette and cream and whisk until smooth.
Season to taste with freshly ground pepper and salt. Peel, devein and wash the shrimp. Cut into butterfly shape. Put the olive oil in a very hot pan and fry the shrimp with the chopped hot peppers until they have taken color on all sides. Add a little salt.
Then immediately remove from the pan. If the shrimp are very large, add the hot peppers later so they don’t burn.
Place the shrimp in the center of preheated soup plates, whisk the soup again, and pour only enough into the plates so that the shrimp can still be seen. Decorate with a basil leaf, serve immediately hot.
