Heat a non-stick skillet on medium heat.
Spread a thin layer of mayonnaise on one side of two slices of bread.
Place the mayo-side down on skillet and build your sandwich (ham, pepperoni, cheese, mustard, etc). Then place a second piece of bread (mayo-side up) on top.
Cook sandwich a few minutes on each side until golden brown.
Cut into two triangles (or leave whole if desired) and ENJOY!