The tartness and brightness of sorrel cuts through the richness of a creamy Troisgros sauce. (Edward Schneider for The Washington Post)

That visit was a big stretch for our budget in those days, and my dominant memory is of how sweet they were to us, encouraging us to order cheap wine (excellent Beaujolais served chilled in a pewter pitcher) and enhancing the least-expensive prix-fixe menu with an extra course or two: One thing I’ll never forget is Jean Troisgros (who died two years later at age 56) coming out of the kitchen and asking if we would mind if he “slipped in” a dish of pan-seared foie gras with lingonberries. (Would we mind?!)

The salmon was one of the Troisgros’s signature dishes of the day; its recipe is given in the cookbook “Cuisiniers a Roanne” (Robert Laffont, 1977; I have the 1982 edition). When I saw sorrel at the market, I knew I wanted to make a version of it, so I walked over to the fish stand to see what might work nicely with a somewhat complex, creamy, citrusy sauce, and I made an unexpected choice: Porgy, or scup as it is sometimes called in our parts.

Porgy with Troisgros sorrel sauce: A blast from the past. (Edward Schneider for The Washington Post)

That sauce, which seemed so new 30 years ago, is in fact a lovely old-fashioned thing. It starts with fish fumet (a light stock), but search as I might, I found none in our freezer. What I did find was a quart of vegetable broth. To make my reasonable facsimile of the Troisgros sauce base (for two or three main-course portions or twice as many small first courses), I took the scraps and bones left from trimming the (skinless) fish into decent portions, sweated them for a minute or two with a thumbnail’s worth of butter and a shallot, then added to the pan 1/3 cup of dry white wine, half that amount of dry white vermouth and a good cup of vegetable broth. If I hadn’t had any vegetable broth, I’d have used water and added an extra shallot and some herbs. I simmered this gently for 20 minutes, then strained it and returned it to the pan to reduce slowly to a syrupy, amber-colored liquid; I left it aside, covered so that it wouldn’t evaporate, for nearer dinner time.

Also in advance, I stripped the leaves from the stems of a medium bunch of sorrel, well washed and drained. This is not a step you can omit, because the leaves wilt into the sauce in a nanosecond, while the stems would remain tough and fibrous. I tore the leaves into a couple of pieces each — they should not be cut into strips — wrapped them in damp paper toweling and refrigerated them until needed.

Assembly was quick: I brought the syrupy sauce base to a boil and added 2/3 cup cream, then simmered it for a few seconds before turning off the heat until the fish was cooked. As for the fish, the simpler the better: salt and pepper; the merest slick of butter in a nonstick pan; fish nicer side down; low heat, covered so that it steams/braises for a couple of minutes; fish gently turned over and cooked until done. You could steam it, too.

While the fish was cooking, I returned the sauce to a boil and stirred in all the sorrel leaves: They immediately collapsed. I finished the sauce with the juice of half a large lemon and swirled in a teaspoon of butter, then checked for salt. I put the fish on warmed plates and spooned sauce around it. (Serve any side dishes — we had new potatoes broken up with peas — on separate plates, just to preserve the beauty of the presentation.)

The sorrel is so tart and bright that it cuts through the richness of the sauce, and the vermouth adds complexity. You’d think the lemon was unnecessary, but I tasted the sauce before I added it, and the citrus really completes the flavor.

It truly was a blast from the past.