In a large saucepan with a heavy base over medium heat, melt the butter.
Add the onions and saute until they are tender and translucent--for about twenty minutes.
Turn the heat up to high, add salt and sugar, and continue to saute until the onions are caramelized. They should be a golden-brown color.
Reduce the heat to medium and then add the flour and continue to cook until absorbed, about two minutes.
Add broth, water, wine, Worcestershire sauce, salt and pepper, and garlic powder.
Bring to a boil.
Reduce heat and simmer for about thirty minutes.
Stir four tablespoons of Parmesan cheese into the soup.
Preheat the oven to 350°F.
Slice the French baguette into slices and toast the slices in the oven until just crusty.
Put one to three slices into each oven-proof serving bowl.
Turn your broiler on.
Pour the onion soup into each bowl.
Top each bowl with a slice of provolone cheese.
Top each slice of provolone with one tablespoon grated Parmesan.
Place under broiler until the cheese is bubbly and brown.