Set a heavy nonreactive saucepan over medium-high heat. Add butter and sauté the cut onions until tender, about 3 minutes. Add the rice, stir well to coat the grains, then deglaze with some of the sherry. Stir well. Add hot broth in stages. As it is absorbed, add more broth to cover. When rice is tender and broth is absorbed (about 25 minutes), finish risotto with whole butter and fresh-grated cheese.

Place a separate skillet over medium-high heat. Add butter and the prepared shrimp. Cook for 2 minutes, or until shrimp turns white. Add the cut-up sausage and spinach and then deglaze with another shot of dry sherry. Pour the sauce over the mixture and heat to wilt the spinach. Set mixture aside.

Plating: Place a large spoonful of risotto in the center of each plate. Arrange the mixture over the rice. Divide the shrimp and chorizo slices evenly among the plates. Spoon any remaining pan sauce on and around the risotto. Garnish with more grated cheese and a fresh herb sprig.