This is a classic french onion soup recipe, and simple to make as well...

Here is what you will need:
5 Medium White Onions
1 Medium Red Onion
3 Tablespoons Olive Oil
9 Cups Beef Broth
1/2 Teaspoon Garlic Powder
1/4 Teaspoon Black Pepper
8 Slices Thick Cut Italian Bread
8 Slices Provolone Cheese
4 Ounces Shredded Parmesan Cheese

Start off by adding the olive oil to a large saucepan and sauteing the onions for around 30 minutes or until they are soft and translucent, but do not brown or caramelize the onions. Now add in your beef broth, garlic powder and black pepper, then bring the contents to a boil. Reduce heat and simmer for maybe another hour. While our soup simmers we can make the bread caps. Place your bread slices directly on the center oven rack and bake at 325 for 15 or 20 minutes (until golden brown).

Once your soup is ready, fill an oven safe bowl about 2/3 full with soup, top off with your toasted bread, a slice of provolone cheese and a pinch or two of shredded parmesan. Now set your oven to high broil and cook the soup for around 5 minutes, or until the cheese is melted and just starting to brown.