Crab fondue

For Onion Puree:
5 tablespoons butter
12 yellow onions, coarsely chopped
2 quarts unsalted chicken broth
1 bay leaf
1 sprig thyme
For Roux:
1/4 cup flour
2 red bell peppers, finely diced
2 green bell peppers, finely diced
2 red onions, finely diced
2 teaspoons cayenne pepper
1 cup heavy cream
1-1/2 cups diced fontina cheese
2 pounds crabmeat
3 baguettes, cubed

1. For onion puree: In a thick-bottomed 4-quart saucepan, melt 1 tablespoon of the butter over medium heat and brown slightly. Add the chopped yellow onions and cook slowly until browned. Add the chicken broth, bay leaf, and thyme sprig. Bring mixture to a boil and reduce heat to a low simmer. Season with freshly cracked black pepper. Cover and braise onions for 2 hours. Remove the onions from braising liquid. Discard the bay leaf and thyme. Boil the broth until it is reduced to 2 cups. Puree reduced broth with the cooked onions in a blender or food processor until smooth.
2. For roux: In the same saucepan, cleaned, melt the remaining 4 tablespoons of butter. Add the flour, stirring constantly, and cook over medium heat for 3 minutes until roux is well blended and blond in color. Add the onion puree and stir to combine. Add the red pepper, green pepper, red onion, cayenne pepper, heavy cream and diced fontina. Stir until cheese is melted, then add crabmeat. When heated through, add salt to taste. Transfer to a fondue pot and serve with cubed baguette.