Preheat a broiler.
With a fork, mix together cheese, tomatoes, garlic, olives and basil. Put bread slices on a baking sheet and place 6 inches under the hot broiler until lightly browned. Remove from the broiler and turn the bread slices over so the soft side is up. Press about a tablespoon of cheese mixture onto the untoasted side of the bread; return to the hot broiler and cook until the cheese is melted and the edges of the bread are toasted, 2 to 3 minutes. Serve immediately.
Do ahead: Without adding the basil, the cheese mixture can be made up to a day ahead of time, covered and refrigerated. The basil should be added just before spreading the mixture on the bread slices.
Makes: 4