Cut the tomato into thicker slices (about 1/4"), Spread a dollop of mayonnaise onto each slice, sprinkle everything bagel seasoning and top it off with grated mozzarella cheese.

Note: If your tomato is very juicy, place the slices on a paper towel before applying mayonnaise, this will help the mayo stick to the tomato slice better.

You could stop there, OR make them even fancier and finish off with a smoked salmon rosette and some greens.

They are best served right away.