4 romaine hearts, damaged leaves removed, trimmed and sliced in half lengthwise
1/2 cup chicken or vegetable stock
1 carrot, chopped
Salt and ground black pepper
1 teaspoon freshly squeezed lemon juice.
Put 2 tablespoons of the butter in a medium to large skillet over medium heat. When butter has melted and foam subsided, add romaine hearts, cut side down, and cook, turning once or twice, until they begin to brown on the edges, about 5 minutes.
Add stock, carrot and some salt and pepper. Cover and cook over lowest possible heat, turning occasionally, until lettuce and carrots are very tender, about 20 minutes. Uncover and turn heat up a bit to reduce any remaining liquid; add remaining tablespoon of butter and gently turn vegetables to coat. Drizzle with lemon juice.