Instructions
Preheat oven to 400F. In a small bowl, stir together the butter, garlic, parmesan cheese and parsley.  Add the salt and generously season with pepper.  Set aside.  Cut deep slits into the baguette 1 inch apart (don't cut all the way through) and place the baguette on a large piece of foil.  Using a spatula, generously spread the seasoned butter inside each slit. Wrap the baguette in foil and place on a baking sheet.  Bake for 15 minutes.  Remove the baguette from the oven and unwrap the top (leave the bread in the foil).  Add a slice of mozzarella (if using) into each slit.  Return the bread to the oven and bake for another 5 minutes, until crisp and golden on top.  Remove from the oven, slice and serve.