Start by sautéing sliced onions and garlic in olive oil until their caramelized, then set them aside.
Next, make a quick tomato sauce. Sauté your tomato paste in olive oil until it caramelizes a bit.
Deglaze the pan with white wine, then add a splash of white wine vinegar, oregano, chopped basil, salt, pepper, and some of the sliced garlic that you sautéed. Stir the sauce until everything is well incorporated, and add water until your sauce is the desired consistency.
Next, slice your loaf down the middle so that you have two equal halves, then spread a little olive oil on the inside of each half.
Spoon your tomato sauce onto each half, then add sliced garlic and onions, cheese, sliced tomato, and basil.
Bake in a preheated oven at 425 degrees, until the cheese is melted and golden brown, then remove it from the oven and top with fresh basil.