These sandwiches are easy and delicious. Mix some olive oil and balsamic vinegar together (a ratio of three quarters olive oil and one quarter balsamic vinegar. Eyeball it…) and then press some lightly toasted sourdough bread on the oil/vinegar mixture and let it absorb for a second. For the other slice of bread, spread with a little mayo. (If you are adverse to mayo then do the oil/vinegar mixture on both slices of bread). Then just layer with slices of burratta cheese, avocado and tomato. Season with a little salt and pepper and you have a delicious sandwich on your hands. Enjoy!