Like butter, the fat from mayo adds flavor, but it tastes more complex and has a more spreadable consistency. It also browns more evenly and has a higher smoke point.
For best results, spread a thin layer of mayo on your burger buns and cook them on the grill for 30 seconds to one minute. Remove and set them to the side while the burgers cook.
Clean the space that the burgers occupied of any leftover burnt bits and grease. Then, with the temperature set to medium-low, gently place each mayo-spread bun over indirect heat.
Watch the buns as they cook and gently press down the center of each bun if the edges seem to be browning faster. Once the buns are golden brown, remove them from the grill.