Let the butter sit on the counter for at least an hour prior to starting the recipe so it softens up.
Preheat your oven to 400F and move the rack to the top third of the oven.
Add the butter, garlic, and salt & pepper to a bowl, then mash together with a fork until smooth.
Cut the loaf of bread in half lengthwise and place each piece cut-side up on a lined baking sheet.
Spread the butter over the cut side of each half of bread, then top each half with the cheddar and mozzarella.
Bake, uncovered, for 12 minutes, and then broil for a couple minutes if needed (watch it carefully so it doesn't burn) to get the cheese extra browned/bubbly.
Meanwhile, warm the tomato bisque in a covered saucepan on the stove until heated through.
Take the cheesy bread out of the oven, sprinkle with the fresh parsley, and slice. Enjoy immediately with a hot bowl of delicious soup!