1. Steam potatoes on steamer rack set in large pot over boiling water until almost tender, about 10 minutes. Add sugar snap peas and steam until peas are crisp-tender and potatoes are just tender, 1 minute longer. Transfer vegetables to large bowl. Cool slightly. Add radishes and onion. Whisk next 4 ingredients in small bowl to blend. Whisk in Parmesan. Season dressing with salt and generous amount of pepper. Add dressing to potato mixture; toss to coat. Season with more salt and pepper, if desired. Serve warm or at room temperature.
2. Per serving: 199.23 (kcal) calories, 40.7 % calories from fat, 9.01 g fat, 1.98 g saturated fat, 5.00 mg cholesterol, 24.01 g carbohydrates, 2.89 g dietary fiber, 1.46 g total sugars, 21.12 g net carbohydrates, 5.81 g protein Nutritional analysis provided by Bon Appétit