Using a cheese grater with small holes, grate the two portions of sharp cheddar cheese.
In a large bowl combine together the flour, baking powder, onion soup mix, basil, garlic powder, and sugar; stir in the grated cheese and chopped green onion.
Gradually pour in the beer, stirring with a fork until just blended and beer is incorporated.
Grease the bottom of a 9"x5" loaf pan and spread the dough in the pan.
Chop the additional green onion and sprinkle evenly over the surface of bread dough for topping (you can substitute chopped thinly sliced yellow onion for this, if you like).
Bake at 350 degrees for 50 to 55 minutes or until a cake tester comes out clean from the middle.
Remove bread from oven; combine the Parmesan and grated cheddar, and sprinkle it over the top of the still-hot loaf.
Let the bread stand in the pan for 10 minutes on a wire rack, then turn out and let cool for another 5 or so minutes before slicing and/or serving.
You can make this bread ahead of time- if you're going to serve it later, wrap it in foil and at the time of serving re-heat it in a 325 degree oven for about 15 minutes; it's really very tasty the day after it's prepared, so you might consider making it a day ahead of when you want to serve it.