Sauce Colbert is a compound butter enriched with meat glaze, tarragon, and lemon that melts into a pool of intensely savoury, herb-scented butter sauce on contact with hot food. It is the canonical accompaniment for sole Colbert (sole butterflied, breadcrumbed, and deep-fried) and grilled meats. The preparation is straightforward but requires quality ingredients: softened unsalted butter is beaten with a tablespoon of dissolved glace de viande, a tablespoon of finely chopped tarragon, a tablespoon of chopped flat-leaf parsley, a squeeze of lemon juice, salt, and white pepper. The mixture is shaped into a cylinder, wrapped in cling film, and chilled until firm. At service, a 1cm round is placed on the hot protein where it melts into an instant sauce — the meat glaze provides savoury depth, the tarragon contributes its characteristic anise note, and the lemon brightens the whole. The butter must be of the finest quality — cultured European-style with at least 82% fat — because in a compound butter, the butter IS the sauce. Cheap butter tastes of nothing; excellent butter tastes of cream, pasture, and sweet dairy. The glace de viande must be fully dissolved and cool (not hot) before incorporation, or it will melt the butter prematurely and create an unworkable paste.
Softened butter beaten with dissolved meat glaze, tarragon, parsley, lemon. Shape into cylinder, chill, slice at service. Butter quality is paramount — 82%+ fat, cultured European style. Glace must be cool before incorporation. Melts on contact with hot protein into an instant sauce.
Roll the butter cylinder in chopped tarragon leaves before chilling — this creates a herb-coated exterior that looks professional and adds extra flavour. Freeze the formed butter for 30 minutes before slicing for the cleanest rounds. If the meat glaze is too thick to dissolve easily, warm it with a teaspoon of Madeira — the wine helps it incorporate smoothly and adds a complementary flavour.
Using warm glace that melts the butter during mixing. Using inferior butter — compound butter amplifies butter quality (or lack thereof). Under-seasoning — the butter needs enough salt and lemon to register as a sauce, not just flavoured fat. Serving at room temperature — the butter should be firm enough to hold its shape and melt slowly on the protein.
Escoffier, Le Guide Culinaire; Larousse Gastronomique