In the course of researching an article on rhubarb recently I discovered that a close relation is sorrel. Oxalic acid makes rhubarb leaves toxic. It gives sorrel leaves a distinct and almost addictive tartness, although sorrel should not be eaten to excess either.
We planted sorrel from seed in the garden at my daughter's school. The plants thrived for a while, but now there's no sign of them. The kids liked the citrusy flavor so much they ate the sorrel down to the nub.
In our own garden we have two sorrel plants. They seem to be perfectly content in average soil amended with compost and fin ull sun with some shade in the afternoon. Sorrel is perenniel and holds up well to our winters here in the District of Columbia. That makes it one of the first greens available in spring when we are still waiting for the rest of the garden to germinate.
Sorrel grows wild as "sheep sorrel" (Rumex acetosella). The garden varieties, (Rumex acetosa), with long, narrow leaves growing in clumps, and "French sorrel" (Rumex scatacus), with smaller, rounder leaves growing in mats, are perhaps best known for their role in sorrel soup. Sorrel will also brighten a salad or omelet and makes a piquant sauce for fish or foul.
The sauce is a fairly simple matter of sweating shallots in butter, "melting" a couple of big handfuls of sorrel leaves, incorporating a bit of white wine and then finishing with a large dose of heavy cream.
I rarely see sorrel in stores. Perhaps one of the vendors at your farmers market will have some for sale. Otherwise, sorrel is so easy to grow, there's no reason not to have some in your herb garden or even in a pot on the deck.
Note: to use the sorrel leaves, remove the stem and tough portion of the vein by grasping the leafing part with one hand and pulling the stem backwards with the other.
2 medium shallots, minced
1 tablespoon butter
2 bunches sorrel, about 20 leaves each, stem and tough vein removed, leaves finely chopped
1/2 cup dry white wine
1 2/3 cup heavy cream
In a medium sauce pan over moderately-low heat, melt the butter and sweat the shallots until soft, about 8 minutes. Add chopped sorrel leaves and "melt" (the leaves will quickly cook down and become extremely tender). Add white wine, bring to a simmer and cook until reduced by about 1/4. Add cream, bring to a simmer and cook until thick enough to coat the back of a spoon.
The sauce can be made ahead and reheated. Here it's used to give the star treatment to a free-range chicken breast from Pennsylvania.