Cold Poached Salmon in Sorrel Cream Sauce

For an elegant buffet, serve this tender salmon blanketed in a rich sauce—a surprising alternative to mayonnaise. Although the coating could not be simpler to prepare (you simply simmer sorrel and cream together for 5 minutes), it tastes as though you’ve spent hours refining and balancing the flavors and texture.

When you use hothouse sorrel, which is large-leafed and sold in big bunches, the amount below should do; if you have wild sorrel, which can be more adamantly tart, use a bi