Line a large baking sheet with parchment paper or aluminum foil.
Slice bread in half, lengthwise, and place on a large baking sheet; cut sides up.
In a medium bowl, mix butter, garlic, parsley and salt together until well combined.
Spread evenly over bread.
Place in the the pre-heated oven and bake for 10 - 15 minutes or until slightly golden brown on the edges.
If using cheese, add at the last 2 minutes of baking.
If a crispier garlic bread is desired, bake for 3 - 5 minutes more, watching carefully until it is as golden as desired.
Notes
Store leftovers covered, at room temperature, for 1 - 2 days. Simply re-heat in the oven by wrapping the bread in aluminum foil and warming, at 350°F, for 10 minutes.