The moisture released by the shredded lettuce gently steams sweet, young peas.
1. Scatter half of the shredded lettuce over the bottom of a wide saucepan. Distribute the peas over the lettuce. Sprinkle on the sugar if you wish. Lay the savory sprigs atop the peas, then scatter on the remaining shredded lettuce.
2. Drizzle the water over the top layer of the lettuce and cover the pan tightly. Place over high heat for 30 seconds or until you hear sputtering sounds inside the pan. Immediately reduce the heat to low and cook gently for 30 minutes. Do not uncover the pan during that time.
3. At the end of 30 minutes, the peas should be tender. Part the lettuce and remove the savory. Add the butter, salt, and pepper and toss until the butter is melted. Transfer to a serving bowl and lay one of the savory sprigs in the center as a garnish.