1 / Peel the onion then cut one half into large cubes and finely chop the second.
2 / Shell the prawns, keeping the heads and shells.
3 / Heat the Dutch oven with a spoon of oil to 2/3 the power and sweat the onions cut into large cubes with thyme.
3 / Add the prawns with the carcasses and color them.
5 / Add 10 cl of white wine and 1.5 l of water then simmer for 20 minutes over low heat. Filter the broth.
6 / Heat the pan to 2/3 the power of the plate and test the drop of water.
7 / Add a spoon of oil and brown the prawns for 30 seconds on each side then set aside.
8 / In the same pan, sweat the chopped onions and pearl the rice so that it becomes translucent.
9 / Add the white wine then 2 to 3 ladles of broth.
10 / Stir regularly until the broth is absorbed by the rice and repeat the operation for about 20 minutes.
11 / Once the rice is cooked, put the prawns in the risotto to reheat them and add the butter with the Parmesan.
12 / Season if necessary.