ON CHRISTMAS EVE eve, a friend paused in her cassoulet-related labors to offer a delicate reproach to me for my use, or misuse, of the term vichyssoise in a recent piece. I had written that an asparagus soup – served warm – reminded me of vichyssoise, but, she said, that could not be, because vichyssoise is always served cold.

Actually, vichyssoise is hardly served at all any more, at least under that name, smudged as it is with memories of Marshal Pétain's collaborationist Vichy regime of World War II. It is called, instead, potato-leek soup, an accurate description that does not capture the soup's simple, wintry elegance; or, sometimes, potage parmentier or potage poireaux-pommes de terre, each of which does suggest a certain Frenchness, though potato-leek soup is also deeply English and, for that matter, American.

What sets vichyssoise apart from other potato-leek concoctions is, according to The New Joy of Cooking, not temperature but fat. Vichyssoises are typically plumped up with some cream or half-and-half, whereas simpler versions consist simply of chopped leeks sautéed in oil (butter, if you like), stock in which to cook the chunks of potato, and salt and pepper. It isn't hard to make the soup vegan-friendly – canola oil instead of butter, water in place of stock – and in my view these substitutions produce a result every bit as satisfying as the creamier, fattier kinds.

In making puree-style soups, there is an issue of widgetry involving the handheld blender, or blending wand, a much misunderstood device that finds its way into plenty of gift-wrapped boxes every December. On Christmas Day I sat with a friend who waxed enthusiastic about chopping spices and nuts with his new kitchen toy. Like many people, he regarded it as a "portable" blender.

"It's good for making soups," I said as tactfully as possible. He looked puzzled, and I explained about the desirability of immersing the blender in the soup instead of having to pour hot soup batch by batch into the stand blender and hoping the top doesn't fly off and send hot, half-blended soup all over the kitchen. For some reason the immersible blender's function is not obvious; I too could not quite figure out what to use it for – I'd inherited one – until one day (I do not remember which day, or the circumstances) the light dawned.

Since then it has been soup, soup, soup: of squashes (butternut, delicata, kabocha), mushrooms, asparagus, bell pepper, most of them colorful, all of them creamy despite having little fat. (Few implements are as useful to dieters.) Oh, and potato-leek too; I've got that one down cold.