Preheat oven to 375°F. Place the bread on a cutting board. Using a serrated knife, make 1" diagonal cuts through the bread, leaving the bottom crust intact. Turn the bread and make diagonal cuts in the opposite direction, creating a crosshatch pattern. Meanwhile, pour the melted butter into the cuts of the bread. Then, use a spoon to drip the pesto into the cuts of the bread. Finally, stuff the shredded cheese into the cuts of the bread. Wrap the bread in aluminum foil and place on a baking sheet. Place in the oven to bake for 15 minutes. Then, open the foil to expose the top of the bread and cook for an additional 10 minutes. Remove from the oven and let cool slightly before serving.