This is our take on a risotto from Certosa di Pavia, a 15th-century monastery in the center of Lombardy’s rice region. Carthusian monks, the very same religious order that created the herb-based liqueur Chartreuse, lived a life of self-sufficiency. They used whatever was around them: rice and the things they found in the watery fields — frogs, small fish, and crayfish. We simplified, it just seemed right.
Peel and devein the shrimp, reserving the shells for the broth, and set aside. Melt 1 tablespoon of the butter with the olive oil in a large pot over medium-high heat. Add the shrimp shells, half of the onions, the celery, carrots, garlic, and parsley stems. Season with salt and pepper, and sauté until golden, about 10 minutes. Add the tomatoes, ⅓ cup of the vermouth, and lemon peel, and cook for 5 minutes. Add 4 cups water and cook for 15 minutes. Strain the broth, then return it to the pot. Add the shrimp and place the pot on the stove, off the heat.
Melt 2 tablespoons of the butter in a heavy deep sauté pan over medium-high heat. Add the remaining onions and cook, stirring constantly with a wooden spoon, until soft and translucent, about 3 minutes. Add the rice, stirring until it is coated with butter. Add the remaining ⅓ cup vermouth.
Add ½ cup of the hot broth, stirring constantly to keep the rice from sticking to the bottom of the pan. Push any rice that crawls up the sides of the pan back down into the liquid. When the rice has absorbed all the broth, add another ½ cup of simmering broth. Keep adding broth and stirring. Taste the rice, it is done when it is tender with a firm center. Add the shrimp and the remaining 1 tablespoon of butter and stir until it has melted into the rice.