Lay out one sourdough slice on a cutting board then slice it into two equal halves. Top one half piece of bread with 1 tbsp pesto then 1 slice of provolone, 1 tomato slice, a few basil leaves, 4 slices salami, a sprinkle of salt and pepper, 1 slice of white cheddar cheese then the second half of the sourdough slice. Repeat with the second piece for sour.
Heat a non-stick skillet over medium-low heat. Coat the pan with olive oil cooking spray. Once the pan is hot, add the assembled sandwiches then cook until bread is golden brown and cheese is melted, about 3-5 minutes. Flip the grilled cheese then cook for another 3-5 minutes on the second side. Enjoy!