Use a sharp knife to carefully cut the top of the head of garlic off. It's okay if some of the cloves fall away from the head. No need to peel any of the garlic at this point.
Place the garlic head and any loose cloves on a square piece of aluminum foil (about 6"x6"). Drizzle the oil over the top of the garlic and then bring the edges of the foil around the garlic and twist to close.
Roast the garlic in the oven for 40 minutes. Remove and let cool.
PREPARE THE CHEESY GARLIC BREAD
Pre-heat oven (or increase, if still heated) to 450°F.
Place the soft butter, parmesan cheese, basil, chives, and salt into a medium-sized bowl. Using your fingers, squeeze out the creamy roasted garlic of the garlic paper-like shells.
Using a fork, mix until the mixutre is blended.
Using a serrated knife, cut the bread in half, lengthwise, into two halves. If desired, trim away the top portion of the bread slice that was the top of the original loaf. This will allow the slice to sit evenly, and also bake more evenly with the other slice (see video for referecne).
Add about 4 to 5 equal dollops of the butter mixture on each bread slice. Use a knife to carefully spread the mixture over the cut side of each slice.
Sprinkle the cheese over the two prepared slices.
Place the bread slices on large baking sheet and bake untl cheese has melted and the edges of the bread are golden brown. Slice and serve hot.
You can roast the garlic up to 2 days in advance. Keep refrigerated in a covered small bowl. Although the roasted garlic has a deeper, yet more subtle flavor, fresh garlic can be substituted for the roasted garlic. Use 3 cloves, minced.Add more cheese if a cheesier bread is desired.Dried herbs can be used in place of the fresh, however, you'll need to cut the amount used in half. Dried basil, parsley, oregano and marjoram all work well together. The bread can be assembled ahead of time and frozen in a large freezer bag for up to 1 month. When ready to serve, remove from the bag and bake at 450°F for 15 to 20 minutes until bubbly and golden brown on the edges.