French Mustard

This recipe creates a stable emulsion by using egg as a binding agent that prevents the oil and vinegar from separating. Cooking the mustard mixture before adding oil denatures the egg proteins, creating a thick, custard-like base that holds the emulsion together. Adding the oil after cooling prevents it from breaking, as heat can destabilize the delicate fat-in-water suspension. The mustard's natural emulsifiers (mucilage) work alongside the egg to create a smooth, spreadable condiment.