Chop up onion and saute in olive oil. Cook and drain broccoli. Puree the broccoli by putting into your chopper and pulse until broccoli is like a paste. You'll have to do a few batches of this. As you puree each batch, put the broccoli into a crockpot. By this time you can also add the onion to the crockpot. Add the four cans of soup. Mix all together. Fill each soup can with the evaporated milk, scraping sides and pouring into crockpot. If you're a little short on the canned milk, just finish up with regular milk. Slowly mix all together. Sprinkle with Parmesan/Romano Cheese. I usually cook this all day in the crockpot but don't have to. A few hours is enough for the flavor to go through.