Preheat the oven to 400° F.
Slice the sourdough bread and spread butter on the slices. Layer the slices in a baking dish.
Toast the bread for 5 minutes in the oven.
Remove the bread from the oven and allow to cool for 5-10 minutes.
Remove the bread from the baking dish and spread ricotta cheese on the bottom of the dish. Then layer the bread back on top of the ricotta cheese.
Generously spread pesto on the slices then place the provolone cheese in between the slices of bread.
Sprinkle the bacon, tomatoes, and mozzarella cheese on top.
Place the dish back in the oven for 10-15 minutes.
Remove the dish from the oven and serve the grilled cheese warm.