TO MOST PEOPLE, sorrel is an herb of little consequence. But in my family, fresh sorrel is a powerful portent of summer, as significant in its own way as the return of the swallows to Capistrano, or the coming of the Copper River kings to Seattle restaurants.

Years ago, my wife Betsy, a clever woman who has a way with sandwiches, put together a grilled blue cheese-and-sorrel thing that sent us both into realms of deepest appreciation.

It's simple, I know, a grilled-cheese sandwich. But when the cheese is blue and the sandwich is layered with shredded leaves of fresh sorrel, and when the whole thing is served with hot tea in the cool breeze of a sunny afternoon in late spring or early summer, then the world is a bright and beautiful place. And when the woman who serves it to you is the love of your life, and she smiles, and maybe even laughs a little as you crunch through the toast and feel the sour, buttery tang of the thing, then you want to experience it again and again. Without the sorrel, it wouldn't be the same.

Serves 2

For these sandwiches, I like to use Diamante bread from Essential Baking Co. - the salt crust and the rosemary leaves add a whole new dimension - or Macrina bakery's potato bread, which has a particularly nice chewy, crisp texture when it's grilled. I like to use Oregon Blue Cheese just because it's somewhat local, but Gorgonzola or the quintessential Roquefort will make the sandwich at least as good, if not better.

4 slices rustic white bread 2 tablespoons butter 4 ounces blue cheese 4 large leaves of sorrel Freshly ground black pepper 1. Butter one side of each slice of bread and put the bread buttered-side-down on a griddle or in a skillet large enough to accommodate all four slices. Turn on the heat to medium or medium high and crumble the blue cheese over the surface of the bread. 2. Stack the sorrel leaves with all the stems pointed in the same direction, and roll them, lengthwise, into a little bundle. Trim off the stem end and cut the bundle crosswise into 1/8-inch slices to make thin little ribbons of the leaves. (Incidentally, this is called a chiffonade.) 3. Distribute the cut sorrel evenly over the surface of the cheese and grill the sandwiches open-faced until the cheese is melted and the buttered side of the bread is browned and crisp. Close the sandwiches and cut each one in half. Serve hot. Print friendly version.

Sorrel, an herb that bears little more than a passing mention in most books about food, has only marginal uses in the traditional kitchen. With virtually no aromatic oil, and a pronounced acid tang, sorrel is unique among culinary herbs. I often say, "It looks like spinach and tastes like lemon." But in all honesty, sorrel is paler than spinach and the sour note is more like rhubarb than lemon.

Rhubarb and sorrel are, in fact, distantly related. They're both members of the buckwheat family, and both the crimson stalks of rhubarb and the pale-green, lance-shaped leaves of sorrel contain fairly large amounts of oxalic acid, rendering them sour, probably slightly toxic, and for those who love them, completely irresistible.

My garden has sorrel in one corner and rhubarb in another, and so, metaphorically speaking, does my mind. Sorrel, as far as I'm concerned, is only used in savory preparations, and rhubarb is more or less reserved for sweet things. There is some crossover - I use both sorrel and rhubarb with salmon - but I would never use sorrel in a pie, and I would never make rhubarb soup.

The name sorrel, which basically means "sour stuff," has been loosely applied to at least three greens containing oxalic acid. "Garden sorrel," also known as "common sorrel," is the kind I grow. It is, as I've said, lance-leafed and pale green; when it's exposed to hot sunlight, its leaves become slightly bronzed around the edges. Botanists call it Rumex acetosa; cooks, as far as I know, never call it that; instead they often call it "French sorrel," but that moniker is better reserved for a round-leafed variety officially known as R. scutatus, which is, for all practical purposes, interchangeable with the lance-leafed kind.

A botanically unrelated third kind of sorrel, Oxalis acetosella, more commonly known as "wood sorrel," is one that's sometimes red. When I was a kid, we called wood sorrel "clover" because it looks something like a shamrock, or a three-leafed clover. That sorrel was as red as rhubarb, but minuscule in its proportions. Lying in the grass on spring and summer afternoons, we used to pluck its leaves and eat them, savoring the tangy oxalic bite. Normally, or frequently anyway, it is not red but green and bears white or violet blossoms on long, tender stalks. It is used, when it is used at all, as a shade-loving landscape plant, not as a culinary herb.

I first stumbled across proper, garden sorrel when a woman who grew herbs for the restaurant where I worked offered me a sample. "It's used in soup sometimes," she said. And sure enough, I quickly found a few recipes for sorrel soup. I started offering it as a special, puréed with caramelized onions and Yukon Gold potatoes. "Some people like it with eggs," she had mentioned. And some of the passing references to sorrel in my cookbooks did mention using it in omelets. I started putting together the occasional sorrel omelet. "But I like it best," my herb grower told me, "with salmon."

Salmon with sorrel is indeed a classic. I promptly started boiling finely cut leaves of sorrel in heavy cream to make a luscious sauce for baked salmon years ago. Then I discovered that this is one of the signature dishes of the famous Troisgros brothers, Jean and Pierre, cooks and restaurateurs in Rouen, France. Bruce Naftaly, the maestro behind that wonderfully strange little restaurant in Ballard known as Le Gourmand, taught me to lighten my sorrel sauce a la Troisgros brothers by simmering the sorrel first in white wine or champagne, then finishing it with the cream.

These, then, were the things I did with sorrel: sorrel soup, an occasional omelet, and a sauce for salmon. I put a sorrel plant in the garden, and it returned each spring with new vigor. I thought I was pretty much in the know. Then my wife made that sandwich and blew me out of the water. Now, I consider blue cheese and sorrel sandwiches the best and highest use for this obscure garden herb, every bit as significant as the salmon sauce of Rouen, as fine and spontaneous a treat as the wild, wood sorrel I plucked from the lawn as a child.

Greg Atkinson, Canlis executive chef, is the author of "In Season" (1997) and "The Northwest Essentials Cookbook" (1999) from Sasquatch Books. Paul Schmid is a Seattle Times staff artist.