Begin heating a nonstick skillet or frying pan over medium heat. Brush the tops of both slices of whole grain bread with the olive oil using a silicon brush or similar. Set one of the slices, oil side down on the nonstick skillet. Lay one or two slices of the cheese on top of the bread slice.
While the underside is crisping up, lay the tomato slices over the top of the cheese slice(s) and drizzle the balsamic glaze evenly over the tomato slices. Layer the fresh basil leaves evenly over the top then top with the second slice of bread, oil side up.
When the underside is golden and crisp, flip the sandwich over to brown the other side (about 2 minutes more).