Preparation

1. Pour balsamic vinegar into a small skillet or saucepan and bring to a low boil. Simmer over low heat until it is reduced by half has thickened slightly. Remove from heat. It will continue to thicken as it cools. Transfer to a container with a lid for storage as you will only need half of it for this recipe.
2. Fill a small bowl with ice water. Fill a small skillet or saucepan with water and bring to a boil. To blanch the basil drop the basil leaves into the boiling water for 5 seconds. Drain and place immediately into ice water to help set the bright green color. Drain the basil leaves and pat dry. Finely chop basil and combine it with the olive oil in a small bowl. Season with a pinch of salt and black pepper.
3. Cut the tomatoes in half lengthwise from the core end to the bottom, Remove core and slice into 1/2" thick slices. Arrange on serving dish or salad plates.
4. Sprinkle blue cheese over tomato slices. Drizzle with 2 tablespoons of the reduced balsamic vinegar. Spoon the basil oil over the top. Season with additional salt and ground black pepper to taste.