Three ingredients are all you need to make this lunchtime favorite.
Place bread slices on cutting board. Use pastry brush to brush melted butter evenly over 1 side of each slice.
Flip 1 slice over (buttered side down), sprinkle with cheese, and press down on cheese lightly. Place second slice of bread on top (butter on the outside) and press down gently.
Place sandwich in 10-inch nonstick skillet and press it lightly with spatula. Heat skillet over medium-low heat and cook until first side is golden brown, 3 to 5 minutes.
Use spatula to flip sandwich over and press lightly again (see photos below). Cook until second side is golden brown and cheese is melted, about 2 minutes.
You need just three ingredients—bread, butter, and cheese—to make a proper grilled cheese sandwich. Start with shredded cheese (or do it yourself, running a block of cheese over the large holes of a box grater). Buttering the bread—not the pan—helps the sandwich brown evenly. Cooking the sandwich over medium-low heat allows the cheese to melt evenly, and pressing it lightly ensures that the bread has good contact with the pan and browns well. You can double the recipe and cook two sandwiches at a time in a 12-inch nonstick skillet.