Bring Butter Sauce Base to a boil; add seasoning and gravy base. Mix thoroughly. Chill until ready to assemble sandwiches.
Sauté ground sausage, onions and celery in butter. Cook until onions are transparent. Add parsley and dry seasonings; mix well. Add chopped cranberries and cranberry sauce; mix well. Remove from heat; add bread crumbs. Mix until stuffing consistency. Do Not Overmix. Divide stuffing in thirds.
On a half sheet tray that has been sprayed with nonstick cooking spray, shape each portion of stuffing into a 1/2-inch thick, 8x12-inch rectangle (same as focaccia). Bake in a 350°F conventional oven for 10 minutes. Cool and refrigerate.
For each Panini, spread 1/3 of butter spread on both cut sides of focaccia. Layer each with 2 pounds of turkey, 1 portion of stuffing and 8 slices of American Cheese.
Press in Panini machine. Cut each sandwich into 8 portions.