How to Make It
In a large nonreactive skillet, melt 1 tablespoon of the butter over moderate heat. Add the shallot, season with salt and cook, stirring, until just beginning to brown, about 1 minute. Add the vinegar and cook, shaking the skillet, until reduced to about 1 tablespoon. Add the cream and bring just to a boil. Add the remaining 3 tablespoons of butter, 1 piece at a time, swirling the pan to incorporate; the sauce will be quite thick. Season with salt and cayenne.
Add the scallops and tomatoes and cook, stirring constantly, until the scallops are just opaque, about 3 minutes. Stir in three-quarters of the sorrel and cook for 30 seconds. Transfer to a platter, garnish with the remaining sorrel and serve immediately.