Preparation Blanch fava beans in a pot of boiling well-salted water 1 minute, then transfer with a slotted spoon to an ice bath to stop cooking. Transfer favas with slotted spoon to a small bowl. Cook Romano beans in same pot of boiling water, stirring occasionally, until just tender, about 5 minutes, then transfer to ice bath to stop cooking. Drain well and transfer to a bowl. Cook green beans in same pot until just tender, 6 to 7 minutes, then transfer to ice bath. Add to Romano beans. Gently peel skins from fava beans (it's not necessary to peel edamame, if using), then add to other beans. Cut basil into very thin shreds. Cook garlic in oil with a rounded 1/4 teaspoon each of salt and pepper in a 12-inch heavy skillet over medium heat, stirring occasionally, 1 minute. Add beans, water, and zest and cook, stirring occasionally, until heated through. Stir in basil and 2 1/2 teaspoons lemon juice and remove from heat. Season with salt and additional lemon juice if desired. Serve beans warm or at room temperature. Cooks' note:Beans can be cooked in boiling water 1 day ahead and chilled.
Preparation Blanch fava beans in a pot of boiling well-salted water 1 minute, then transfer with a slotted spoon to an ice bath to stop cooking. Transfer favas with slotted spoon to a small bowl. Cook Romano beans in same pot of boiling water, stirring occasionally, until just tender, about 5 minutes, then transfer to ice bath to stop cooking. Drain well and transfer to a bowl. Cook green beans in same pot until just tender, 6 to 7 minutes, then transfer to ice bath. Add to Romano beans. Gently peel skins from fava beans (it's not necessary to peel edamame, if using), then add to other beans. Cut basil into very thin shreds. Cook garlic in oil with a rounded 1/4 teaspoon each of salt and pepper in a 12-inch heavy skillet over medium heat, stirring occasionally, 1 minute. Add beans, water, and zest and cook, stirring occasionally, until heated through. Stir in basil and 2 1/2 teaspoons lemon juice and remove from heat. Season with salt and additional lemon juice if desired. Serve beans warm or at room temperature. Cooks' note:Beans can be cooked in boiling water 1 day ahead and chilled.