Preheat the oven to 400°F. (it could be a little more or less if you're baking something else at the same time that requires a specific temperature.
Get your nice big loaf of bread. Don't shy away from ones that already have some sort of flavor or seasoning. Check that day old bin!
Slice your loaf of bread into slices about 1 inch thick, leaving them still attached at the bottom crust. Do this slicing on a cutting board or the bread bag. If you do it on your cooking foil, it'll just slice that up.
Spread butter on each side of each slice of bread.
Sprinkle garlic powder and a little tiny bit of salt (if desired) between each of the buttered slices.
Sprinkle Parmesan cheese between each of the buttered slices (if desired).
Transfer bread to large sheet of foil...
...and fold up the ends over the ends of the loaf and wrap up the sides and seal.
Cook in oven for a half hour or so. Longer shouldn't hurt it if it's sealed well.