Making a grilled cheese sandwich is simple, but swapping butter for mayonnaise on the outer sides of the bread can take it to the next level. Mayo spreads more easily than butter, creating an even layer that helps the bread brown perfectly in a skillet over low heat. It results in a crisp, golden crust while giving the cheese time to melt thoroughly inside.
Mayonnaise also has a higher smoke point than butter, so it won’t burn as quickly, allowing for more even cooking. Its blend of egg and oil adds a subtle richness that enhances the sandwich’s flavor. This small tweak creates a grilled cheese that’s crispier, creamier, and more consistent—making it hard to go back to butter once you’ve tried it.