Bring a large pot of water to the boil, add 1 teaspoon of salt and then the linguine and cook according to the directions on the package.
Keep back 1 cup of the pasta water when draining the pasta, which can be used to loosen the sauce if necessary.
Now melt 1 teaspoon of the butter and 1 teaspoon of olive oil over high heat in a heavy based frying pan and add the tomatoes, tossing the pan and allowing them to blister slightly on the outside and then set these aside.
Add another splash of olive oil, if needed, and a teaspoon of butter to the pan and add the halved prawns, shell side down first, and sauté until the shells have just turned pink. Turn over and cook the other side, and add the garlic into the mix at this stage, stirring well, being careful not to burn.
Add the stock to the cooked prawns and warm through.
Remove from the heat, add the parsley, lemon zest, lemon juice and chili flakes and stir.
Add the cooked linguini to the prawns and sauce, toss well, then add the tomatoes. If the pasta sauce is too thick then add a splash of pasta water or more stock if you prefer.
Top with the rocket, stir through and garnish with chopped parsley.