In a medium bowl, toss tomatoes, shallot, garlic, balsamic vinegar, 1 tablespoon of olive oil and basil. Toss to combine. Toss in cheese, if using.
Cut baguette into 1/3-inch thick slices on a slight angle. Heat 1/2 tablespoon of butter and 1/2 tablespoon of olive oil in a large skillet over medium-high heat. Add the baguette slices and cook until toasted on the bottom; flip and cook until lightly toasted on the top. Remove toast pieces to a plate and repeat with remaining bread.
Top toasted bread with tomato topping and garnish with additional basil or cheese, if desired.