Hi Val., here is my tried, tested and true Mother Arlette recipe:
1. Bring a big pot of salted water to a boil. (because lettuce tends to shrink quite a lot)
2. When water is at a rolling boil, precipitate the lettuce in it for a quick boil. until the lettuce is just limp, but still uncooked
3. Drain really well, really well
While the lettuce is draining...
4. Prepare your MORNAY sauce (white sauce with sharp cheese) [Recipe available on the internet]
5. In an oven proof glass dish, lay down the lettuce, pour MORNAY sauce over it, add a pinch of sugar (Kills bitterness), lots of fresh nutmeg, salt, pepper, if you like, a bit of shredded ham (optional), cover with thin slices of butter and breadcrumbs, cook in the oven to taste. .... et voila!
Belgians also make a fresh Endive salad, but the endive is mixed with other types of lettuce like "ESCAROLLES", and a pinch of sugar is added to the dressing to mitigate the bitterness.