Melt cheese at a low temperature for a short time, stirring often. Cheese needs just enough heat to melt and blend with other ingredients. If heated too long or at too high a temperature, the cheese can become tough and stringy, and the fat can separate. Cheese melts more quickly when shredded or cubed. Shred it when cold for easier shredding. A process cheese (such as Velveeta®) will melt evenly and smoothly with no fat separation. Process cheese can be cubed to speed up melting time. Shred natural cheese so it will melt quickly at a low temperature. When cheese is used to top an entrée, add it near the end of the baking time so it has only enough time to melt.