Working over a small bowl, rub thyme leaves between your palms until finely powdered. Place a large steamer basket in a Dutch oven; add water to just below the steamer bottom. Add peas to the steamer; top with scallops in a single layer, touching each other as little as possible. Sprinkle with the powdered thyme, 1/4 teaspoon salt and 1/4 teaspoon pepper.

Cover the pot and place over high heat. When steam begins to escape, start timing. Steam for 3 minutes. Add pea shoots (if using), cover and continue steaming until the scallops are just cooked through, 2 to 3 minutes more. Remove from the heat.

Meanwhile, whisk oil, lemon zest, lemon juice and the remaining 1/4 teaspoon salt and 1/4 teaspoon pepper in a small bowl until combined. Spoon the scallops, peas and pea shoots (if using) onto a serving platter, drizzle with the dressing and serve immediately.

Shopping Tip: Pea shoots, sometimes called "pea tendrils" or "pea sprouts," are the tender vines and leaves of pea plants. Sweet in flavor, with a delicate crisp texture, they can be found in the spring at farmers' markets, Asian markets and some supermarkets. They're best used immediately, but can be refrigerated for up to 2 days. Or use small sprouted pea plants (they resemble large, straight alfalfa sprouts), labeled "pea shoot" or "pea sprout," found with the produce in well-stocked supermarkets.