2. Drain the potatoes (you may use the same water to blanch the green beans, below), then plunge them into a large bowl filled with ice water to stop the cooking. When they're cool, drain again. Toss them in a large roasting pan with the olive oil and the garlic.
3. Preheat the oven to 500 degrees Fahrenheit. Roast the potatoes, tossing them occasionally, until completely tender and lightly browned, 15 to 20 minutes. Toss with the parsley, salt, and pepper, and serve.
Adam Rapoport, editor in chief of Bon Appetit magazine and the website www.bonappetit.com, knows his way around a grill. He has edited an entire book on the subject: The Grilling Book: The Definitive Guide from Bon Appetit.