Lemon and Shrimp Risotto with Fresh Basil

This is our version of the rich, intensely flavored risotto di limone that Giovanna Aceto taught us to make in Amalfi, Italy. In an unusual twist, the risotto is finished with an egg yolk and a couple tablespoons of cream, giving the rice a lush, velvety taste and texture. To create a flavorful broth for simmering the risotto, we steep the shrimp shells and strips of lemon zest in water, and for citrus notes that register at every level, we stir in bright, puckery lemon juice and floral, fragrant grated zest just before serving. If you purchase shrimp that are already shelled, bottled clam juice is a fine substitute. Bring two 8-ounce bottles clam juice, 3 cups water, ½ teaspoon salt and the zest strips to a simmer in the saucepan and cook, covered, for 10 minutes to infuse, then strain as directed.