Preheat grill pan or Panini press. You can also use a George Forman grill.
Melt butter and mix with olive oil.
Peel eggplant and slice.
Brush the eggplant slices with butter and oil mixture. Season lightly with salt and pepper.
Grill eggplant on the grill pan until the eggplant is marked and just soft, about 4-6 minutes. Turn once.
Remove from the grill.
Mix worchestershire, basalmic vinegar, mayonnaise, garlic powder and mustard in a small bowl.
Spread mixture on four slices of bread. Add sliced eggplant, add 1 T red onions, and a few chopped tomatoes to each sandwich ( you may use fresh tomatoes, if desired. Because this recipe was developed for a contest, canned tomatoes were used).
Add chopped cilantro.
Add 1 slice mozzarella to each sandwich.
Top with remaining bread slices.
Brush both sides of bread with olive oil and butter mixture.
Grill until cheese melts and bread is crisp.
Serve with marinara sauce or picante sauce, if desired.