The tuna melt combines bread, canned tuna, mayonnaise, and sliced cheese to create a tasty and convenient hot sandwich. While the way you prepare your tuna and the kind of cheese you use will define the flavor of your melt, there's one ingredient that shouldn't be overlooked when it comes to preparation.

The proportion of bread to filling can make or break any sandwich, including tuna melts. For the best bread-to-tuna ratio on tuna melts made with two slices of bread, Serious Eats recommends making two sandwiches per one five-ounce can of tuna, and the bread slices should be about a half inch thick each.

If you want an open-faced tuna melt using only one slice of bread, use a slice that is two times thicker, or 1 inch; also, choose a sturdier and heartier bread that won't be overwhelmed by all the filling. Slicing your own bread is the best way to ensure that your sandwich ratios are always perfect.