Cocoa butter extenders are vegetable fats that can be blended with cocoa butter in limited amounts without significantly changing its physicochemical properties — its melting, crystallization, and snap. They stretch expensive cocoa butter a little further while keeping the chocolate’s behaviour essentially intact. The distinction from equivalents and substitutes is one of degree: extenders supplement rather than replace. Manufacturers dose them carefully and validate tempering, since even small fat-system changes can shift bloom resistance and mouthfeel in the finished bar.