Spread four slices of bread with mayonaise on the “outer”
edges (since you’ll be making sandwiches).
Place a cheese slice between each pair of slices of bread,
laying the sandwiches on the cookie sheet.
Bake for four to six minutes, then flip the sandwiches
and bake for another three to five minutes. Note that the
sandwich will brown on the bottom (the side facing the foil), and
not on the visible (top) side when it’s in the oven.
Tips and Suggestions
Use real mayonaise, not “salad dressing”, as this intended to
promote browning and needs a decent fat content. If mayonaise is
not available, you could probably substitute margarine or butter.
I tested this with “Thin Sandwich” bread, which has 24 slices in a
single loaf, and with “Thick” cheese slices. You’ll want to adjust
the baking time and temperature if using something different.
You can probably fit three sandwiches on a cookie sheet, but I
can’t eat that much all at once.