You can put lettuce and other salad greens into almost anything, they're usually mild and tender enough that they don't overpower. I used to do it with greens that bolted. Any bitterness disappears with cooking.

I made this soup last summer, but thought it was a lot of work for what it was. It was pretty good, though, and maybe you could use it as a starting point...

https://www.geniuskitchen.com/recipe/cream-of-lettuce-soup-21707

Annie

I made a soup similar to the one Annie has posted, without the green pepper or watercress and it was delicious and delicately flavoured.

Over here, spring greens are a cabbage that would be delicious in this:

http://www.oliviascuisine.com/caldo-verde/

If Its lettuce, add it to some pea soup.

I used to make a lettuce and tomato soup years ago.

It was just gently frying half a sliced onion with half a sliced lettuce in butter. I think it had to be an iceberg or romaine (cos) lettuce... problems I know. Add a cut up tomato, salt and pepper and either water or chicken stock about a litre. Simmer about half an hour.

This was also a delicate flavour. Had to be butter.

I have had cheeseburger soups that had lettuce in them. I don't have a recipe but I am sure they are all over the internet. It was pretty good.

For lettuce soup or cooked lettuce, cut the midribs and stems out and cook those first before adding the blade part of the leaves.

Midribs and stems take a lot longer to cook. You don't want to end up with mushy lettuce.

A little more work, but worth the effort.

Also, don't add salt if you are stir frying. It gets very watery. A few teaspoons of oyster sauce on top at the end is all you need.

dcarch

Reporting back on the lettuce in soup. We made potato soup tonight with onion, celery and some organic yellow potatoes. We used non salt chicken broth and vegetable bouillon, seasoned with Mrs. Dash Garlic and Herb seasoning. I added lettuce and a big hunk of neufchatel cheese at the end and lightly blended it with a stick blender. Topped with grated smoked cheddar cheese and a few bacon bits. It was very good!

Yum, L, it sounds really good, I'll have to remember that when I have leftover fresh greens.

Annie

Sorry I'm so late to this post, but the old Chalet Suzanne restaurant in Lake Wales, FL was famous for its lettuce soup, known as "moon soup" since a can of it went to the moon with the Apollo astronauts. It's an excellent soup, one I often make when my romaine is bolting. (It does call for romaine but I expect you could use any relatively sturdy lettuce.)

The recipe and a variant are in this blog post:

http://www.coracooks.com/2011/05/romaine-lettuce-soup.html

ETA Forgot to say, I don't know if the canned variety is still available, but I would avoid. It's a very delicate flavor and the canned version is not anything like it is when made fresh.