Remove the stems from the portobella mushroom caps. Brush portobella mushroom caps with extra virgin olive oil, coating both sides very well. Place portobella mushrooms on heated grill. Let cook several minutes on each side. You will know the grilled mushrooms are done when they turn a darker color and look moist and slightly shrunken.
Slice ciabatta bread into 4 thick slices and toast until slightly brown.
Tear fresh mozzarella into thick long chunks and divide evenly amongst the bruschettas. Top with slices of sundried tomato (about 5 small pieces to each) and little rosemary leaves. (Note: can be served fresh or can further melt the cheese for a hot bruschetta by placing the bruschettas under a hot oven grill for a couple of minutes)
Sprinkle with cracked black pepper and extra virgin olive oil just prior to serve.