Marinate chicken breast overnight or for a few hours in 1/2 cup of olive oil & 1/4 cup of Balsamic vinegar. Cut into slices.
Cut baquette into slices (not too thin) and grill for a few minutes to get toasty. (Brush w/ some garlic butter or w/ Italian dressing or balsamic & oil for extra flavor!) Top w/ slices of mozzarella, chicken, & grill until cheese is melted.
Remove & top w/ tomato slices (I used roasted red pepper in place of tomato for my tomato-hating daughter) and a fresh basil leaf on each crostini slice. Sprinkle with some more vinegar & oil & some parmesan. You can add garlic to this, as you desire.