Make sure to rinse your basil. Especially if it is farm fresh. Need to make sure to get all of the dust off the leaves.
In a food processor combine the basil, garlic, and pine nuts in a food processor and pulse until coarsely chopped. Add 1/2 cup of the oil and process until fully incorporated and smooth. Season with salt and pepper. If you like your pesto a little on the runnier side you can add a tad more oil, or even a little water if you want it to be a tad bit healthier.
Set aside the pesto.
Preheat your oven to 375 degrees Fahrenheit.
On a cutting board, slice the bread loaf into 1 inch wide cubes (making sure to not cut all the way through the bread. Try to leave at least 1/4 inch on the bottom). Make cuts roughly 3/4 to 1 inch apart. Turn the loaf 90 degrees and make another set of cuts roughly 3/4 to 1 inch apart. This will give you perfect cubes.
Place the bread onto a double sheet of aluminum foil. Curl up the edges and then pour the melted butter over the loaf. Spreading the cubes apart as you pour the butter.
Then add break the mozzarella cheese slices into 1 inch wide sections and place them in between the cubes.
Then pour the pesto over the loaf, using a spoon to get the pesto into the spaces between the cut cubes.
Finally top the bread with Parmesan cheese. Seal the foil around the bread.
Bake for 15-20 minutes or until the cheese melts. Then unwrap and continue to bake for 10-15 more minutes or until the cheese browns.
Unwrap, serve and enjoy!