Cut baguette into two six-inch lengths and then slice each length in half. You should have 4 pieces. Two tops and two bottoms.
Spread basil pesto on the tops and bottoms. Slice the fresh mozzarella and layer it onto the bottoms of the bread. Slice tomatoes and layer on top of the mozzarella. Drizzle red wine vinegar over the tomatoes. Sprinkle on some salt and pepper, and then close the sandwich with the other bread.
Notes
Whether you use fresh basil or basil pesto is entirely up to you. I recently published an incredible recipe for basil pesto that you can refer to, or you can always purchase basil pesto. If you use fresh basil, I would also drizzle some good extra virgin olive oil into your sandwich for added moisture and flavor. Store your unused basil in water like fresh cut flowers. Do not put it in the fridge.The red wine vinegar and tobasco sauce are not traditional in a caprese, but they are wonderful. I find these additions really heighten the flavors and make the sandwich more digestible. Vinegar and spice helps to cut through the richness of the cheese, pesto, and bread, and it really gets your digestive juices flowing. If you are going to use just one of these, choose the red wine vinegar. Trust me. It is amazing!