Preheat the oven to 325 degrees.
Melt the butter in a large pot over medium heat. Add the onions, red peppers, celery, garlic, salt, and cayenne and cook, stirring, until the vegetables are soft, about 15 minutes.
Increase the heat slightly, and add 1 1/2 cups of the fish stock. Dissolve the cornstarch in the remaining stock and add to the pot. Bring to a simmer then reduce the heat to medium-low and cook until the mixture is well thickened, Add the crabmeat, scallions and parsley and warm through. Add more cornstarch mixture if your crabmeat is very moist and isn’t creating a nice thick blend).
Pour the mixture into a bowl and cool in the refrigerator.
Place 2 one-pound French bread dough balls on a floured surface and roll out to 1/2-inch thick rectangles (about 4x8 inches).
Divide the filling into four parts and spread two strips of filling lengthwise onto each rolled-out piece of bread dough, leaving space between the two strips.
Fold about one inch of each end toward the center. Then roll the dough, using the long side, into a cylinder like a cigar. Seal the ends with a dab of water.
Bake for 40 minutes and enjoy with a glass of dry Riesling or crisp Viognier.
Makes two loaves