Quick Lobster Stock
Bring 6 cups of water to a boil, add fresh or thawed lobster and continue to boil for 4 minutes. Remove lobster and plunge into ice water. Remove the lobster meat and dice for the risotto, then refrigerate. Return the shells to the boiling water.
Add onion, carrot, celery, tomato, bay leaf then add salt & pepper to taste. Simmer the broth for 20 minutes then strain out the lobster shells, vegetables and spices. Reserve broth and keep on medium heat for use in the risotto.
Lobster Risotto
Bring a large skillet or frying pan to medium heat, add olive oil, shallots and garlic. Cook until softened (1-2 minutes). Add the Arborio rice, cook (stirring occasionally) for 1-2 minutes before adding dry white wine.
Add wine and cook for a minute, keeping the rice moving (stirring frequently). Add one-third to half of the lobster stock, cook (stirring occasionally) for 3-5 minutes until the rice has absorbed most of the liquid.
Add the remaining lobster stock in ladled increments, allowing the rice to slowly absorb the liquid until the Arborio rice becomes slightly translucent and is an al dente firmness and the core can still be seen in the center (about 20 minutes total time once broth is added).
Add the reserved diced lobster meat, butter, mascarpone cheese, lemon zest and salt & pepper (to taste). Stir vigorously until all ingredients are well combined and a thick, creamy risotto is achieved. Check the seasoning and garnish with extra Parmesan and chopped chives