Heat 2 tablespoons olive oil in a medium saute pan, add garlic, and stir for about 30 seconds. Add peeled fava beans and saute them over medium-high heat, stirring almost constantly, for 3 to 4 minutes, or until they color lightly. Add 1 tablespoon lemon juice, sprinkle beans with a big pinch of sea salt, give them one more stir, and remove them from heat. Set them aside as you prepare rice.
Heat remaining 3 tablespoons olive oil in a large saute pan and stir shallots in it over medium heat, with a dash of salt, until they are soft, 6 or 7 minutes. Bring vegetable broth to a simmer, cover it, and keep it hot on lowest flame. Be sure that your vegetable broth is not too strong or salty.
Add rice to the shallots and stir over medium heat for 2 to 3 minutes. Add wine and stir as it evaporates. Add 1 cup of hot vegetable broth, lower heat to a simmer, and stir as broth is absorbed into rice. Continue adding broth, about a cup at a time, stirring almost constantly. As each cup of broth is nearly absorbed, add next cup and stir again, and so on until rice is tender but firm and a creamy sauce has formed around it, 20 to 25 minutes.
Stir in remaining 2 tablespoons lemon juice and lemon zest, as well as ⅔ of the sauteed fava beans, reserving rest for a garnish. Stir in Parmigiano, and then, just before serving, add a final, generous ladleful of broth. Immediately spoon risotto into shallow bowls and scatter a few reserved fava beans on top of each serving. Pass olive oil carafe and additional grated Parmigiano-Reggiano at the table.
A Seafood Variation: Lemon risotto can be made with shrimp instead of fava beans, or along with them. Peel and devein about 1 pound of fresh shrimp, wash them and have them ready as you begin to cook risotto. When rice has been cooking about 15 minutes, saute shrimp for a moment in some olive oil with a bit of garlic and a splash of white wine. Stir shrimp into risotto, or into part of it, just before serving. Or add a few sauteed shrimp on top of individual servings. The large Prawns Sauteed with Garlic, which are left unpeeled, also make a good pairing.
About Those Fava Beans: The well-protected fava beans must first be taken out of their large pods; then the beans need to be peeled, one by one. It’s a bit of work, but not so much that it should stop you. I timed myself the last time I peeled a pound of shelled favas (about 3 cups beans in their jackets): 20 minutes. Not a tragedy. So bring a pot of water to a boil and drop in the shelled favas. When the water simmers again, give them 2 to 3 minutes, depending on their size. Drain them, rinse briefly with cool water, and then slip off their skins while they are still warm. You’ll have a generous 2 cups when the beans are peeled.