We who cook with whole farmed scallops know a secret or two. Do not overcook the tender scallop morsels.
Here’s another secret: the cheeses we so often like to pair with scallops are not only mild in flavor, they are delicate too. Too much heat, heating either too hot or too long, causes the protein nets to squeeze out the fats and the water so you end up with tough scallops or rubbery cheese in a puddle of grease.
Enzymes link amino acids to form proteins in cheese. That produces a structure quite similar to gluten, but these nets collapse in heat. The fats and milk proteins now flow out of the curd. Processed cheeses such as Velveeta® have enzymes and emulsifier additives in them that stabilize them. Look closely at the labels on cream cheese and even Alfredo sauce and buried in all those chemical terms is the secret to their wonderful mouth feel.
Secret #3 Be gentle with the heat. Bits of shredded cheese each spend less time in that dangerous melting phase than would bigger blocks of cheese. Let the shreds (or scallops!) sit a bit at room temperature to warm up and then use low heat.
Good choices for melting are cream cheese, Velveeta, Asiago, Cheddar, Emmentaler, Fontina, Havarti, Monterey Jack, Muenster, Gouda and Gruyère, Brie and Camembert. (Most cheeses are quite high in sodium so, as with our scallops, you probably want to hold back on adding salt.)
Cheeses that still contain high levels of whey proteins will soften but not melt. Goat cheese, feta, paneer, cottage cheese and ricotta will not give you that creamy mouth feel.