Hmm, I wondered, was this different from split pea soup (soupe de pois casses)?

As it turns out, it is fresh pea soup. You saute some sliced tender leaf lettuce in butter, add young peas (frozen are best, unless you have some just-picked fresh ones), cover with water and simmer, covered, for about 40 minutes. Puree, season, and it's wonderful — silky and sophisticated as Duke Ellington's lady, with very pure pea flavor. Stir in some lemon zest or chopped mint at the end, if you like.

A few years later, when my son was a baby, and I was determined to get him to eat vegetables, I simmered broccoli in some chicken broth till the broccoli was tender, put it all, vegetable and broth, in the Cuisinart, and pureed. Voila! — a silky, dark green, nutritious soup that he slurped up with glee.

In my naivete, I thought this dish's best attributes were that it was quick (only 15 or 20 minutes for the broccoli to get tender) and an easy way to sneak cruciferous vegetables into my unsuspecting son's diet.

But I kept admiring the way it looked — so green and creamy, despite the fact there was no cream in it — and I could never help myself from taking a few spoonfuls. Delicious. Sometimes I used cauliflower, sometimes baby bok choy. Always, it was a pure expression of the starring vegetable. I started making it for the whole family, and even serving it at dinner parties. Naturally, I seasoned ours more assertively than the baby's. When I realized that this was the easiest first course in the universe — no more work than making a salad — it turned into a habit.

Once I thought about it for half a minute, I realized I hadn't invented it. It's the same technique Julia Child used for one of my longtime favorites, potage parmentier — the leek-and-potato soup that she called "simplicity itself." You just simmer sliced leeks and potatoes in water, pass them through a food mill (I always used a food processor; a mill makes it even smoother) and stir in a little cream or butter and parsley or chives. Use chicken broth instead of water, chill it, and it's vichyssoise. Toss in a big handful of watercress five minutes before it's done, and it's watercress soup.

Then there's my most frugal yet luxurious soup, a puree of asparagus. When fresh asparagus makes its appearance, first I go through an asparagus vinaigrette phase. I peel the spears, simmer them gently in salted water, drain them and sauce them with a vinaigrette. But don't throw away the asparagus cooking water: Freeze it to use as a base for a creamy asparagus soup. Once you have about a quart, use it to simmer two bunches of unpeeled asparagus until they're just overcooked. Then puree. It's asparagus heaven.

But it's the chicken broth-based purees that are the quickest and easiest: Roughly cut up some vegetables, add a carton of good chicken broth, turn on the heat, and you're almost there. If you use an immersion blender, you don't even have the fuss of transferring the liquid to the bowl of a food processor or blender.

Best of all, you can dress them up or dress them down. Toss in extra vegetables — whatever's in the fridge. Or give them a dapper garnish, depending on the soup.

The broccoli soup is terrific as is, one of those cases of the whole adding up to more than the sum of its parts. Or you can finish it with a little lemon juice or zest, stir in some creme fraiche or butter, or sprinkle on a bit of grated parmesan. This one works just as well with cauliflower. If you want something richer, stir in some cream.