Arrange sliced Italian bread flat on a baking sheet and cover with foil. Set aside until ready to use.
Combine sour cream, thyme, red pepper, cayenne pepper and four cheeses in a large bowl and blend thoroughly.
IF SERVING FAMILY-STYLE:
Spray an 8x10-inch casserole dish with pan spray, then use a spatula to transfer the mixture.
FOR INDIVIDUAL SERVINGS:
Spray eight individual heat-resistant serving bowls, such as souffle cups, with pan spray and fill each with 1/2 cup of mixture. Place individual bowls on a baking sheet. Using a large spoon, spread cheese mixture to create an even surface.
Place casserole dish or baking sheet with individual bowls on center rack in oven.
After five minutes, place baking sheet with bread, still covered, on top rack in oven. Bake for an additional five minutes. Remove bread and fonduta from oven.
Garnish casserole dish with diced tomatoes and parsley in center of fonduta or divide evenly among smaller bowls. Arrange bread slices around bowl(s) and serve immediately.
*This recipe calls for one of these two cheeses to be smoked and one to be regular).