These cute little appetizer burgers can be mixed and shaped ahead of time. Just cover and chill them until you are ready to grill. Chose your plum tomatoes small enough to be about the same size as the quarter slice of bread and your baby burgers.
Shape each portion into a ball and flatten to a 1/2 inch thick patty about 1 1/2 inches in diameter.
Thread 4 patties horizontally on metal skewers, leaving space between each one. (I have found that using 2 skewers works better then one. Thread them the opposite ways to make turning them over easier if you need to turn them.).
Place patties on the grill; cover and cook 8 to 10 minutes (turning once if necessary) or until no longer pink in the middle.
Top each patty with a piece of cheese.
Place each patty on a quarter piece of the toasted bread.
Top the burgers with a pickle slice, a tomato slice and another toast square.
Spear burgers with a toothpick to hold all the layers together.
Serve with ketchup, mustard, mayo and thousand island salad dressing for dipping.