In a heavy bottomed roaster or pot, add the butter to the pot, and when it melts,
add the sliced onions, sprinkle them with the garlic salt, and seasoned pepper, and toss them in the pot.
Saute the onions, until they're lightly caramelized, then turn the heat to low
stir in the brown sugar and bacon, and toss the onions and bacon evenly in the sugar. let simmer for 10 minutes.
Add the bullion cubes, and water, and turn heat to medium.
Make sure the bullion cubes dissolve in the water, and stir occasionally.
Let the soup simmer for about 15 minutes, making sure the bullion has dissolved.
Slowly, stir in the flour, and thicken the broth just a bit.
Let soup simmer again for about 10 minutes, over low heat.
Turn off heat, and place soup bowls, or dishes on a sturdy cookie sheet lined with parchment paper.
Ladle the soup into large soup dishes.
Place one or two of the crusty pieces of bread on top of the soup, and place 2 or 3 slices of the Swiss cheese on top of the dishes.
When all soup dishes are filled and topped with bread and cheese, place the cookie sheet in the oven, under the broiler until the cheese is bubbly, and golden brown on top.
When cheese is browned, remove the cookie sheet from the oven, and place the soup dishes on plates.
Serve at once. Enjoy!