Preheat your grill.
Cut bread into 1-inch slices, then brush with olive oil. Skewer tomatoes, then lightly brush with olive oil. Place both the bread slices and skewered tomatoes on the grill. Flip bread when crisp. Rotate tomatoes and remove before splitting, about 3 to 5 minutes.
Roughly chop basil, then place in a mixing bowl. Add 1/4 cup olive oil, balsamic vinegar and salt and pepper, to taste. Slice grilled tomatoes in half and add to basil mixture. Mix to combine.
Slice mozzarella balls and set aside.
To assemble bruschetta: Place grilled bread on a serving platter, arrange 2 to 3 slices of mozzarella on each slice of bread. Place 2 to 3 spoonfuls of the tomato mixture on top of the cheese. Top with few grinds of fresh pepper, if desired.