The trick to a successful vinaigrette, says Annie Somerville, is to start with the acidic ingredient and mix everything with that before adding the oil. She also favors an oil-to-acid ratio of 2:1, rather than the traditional (and heavier) 3:1 ratio. Meyer lemons make this dressing extra-special, but regular lemons work well too.
1. To make Vinaigrette: Whisk together lemon juice, zest, and salt. Slowly pour in oil, and whisk until dressing is emulsified.
2. To make Salad: Have large bowl of ice water ready. Bring large pot of salted water to a boil. Add peas and sugar snap peas, and boil 1 minute. Drain, and immediately dunk vegetables in ice-water bath. Drain well, and transfer to large bowl.
3. Add radishes and carrots to peas mixture; toss with 1/4 cup Vinaigrette (reserve remaining Vinaigrette for another use). Gently stir in pea shoots.