Peel onions, slice in half through the core, and then cut the halves into 1/4-inch-wide slices.  

Saute onion in butter in frypan on medium heat setting until they are translucent. Set aside.

Bring water to a boil and add onions, beef bouillion concentrate, pepper and garlic powder. Simmer on medium heat setting for at least 25 minutes. 

Remove from heat and transfer to 6 soup bowls (with handles). Top with croutons and swiss or mozzarella cheese.  Serve.

OR if desired, transfer bowls to cookie sheet and broil in oven for 3 minutes. CAUTION - soup bowls will be hot!