This was completely counterintuitive. We think of lettuce as the light, crisp, fresh base for a salad. The thought of cooking lettuce seems bizarre. But many times while flipping through the pages of Mastering the Art of French Cooking I have seen this recipe and I knew that one day I would attempt it.
I did, and it's delicious! Slow cooking in rich stock tames the lettuce and makes it fascinating and wonderful.