Lightly toast and butter the bread. Cut it into squares or triangles and place a layer in a buttered casserole. Cover with a layer of thinly sliced cheese, dust with Parmesan and seasonings and repeat these layers; the top should be cheese, dusted with mustard and paprika. Beat the eggs well and add enough half milk and half cream, or rich milk, to make 3 cups. Add Worcestershire sauce. pour over the casserole and allow to stand for at least one hour, occasionally depressing with a wooden spoon so that the liquid covers all of the ingredients. If necessary add more whole milk. Preheat the oven to 400 degrees F for at least 10 minutes, cover the casserole with a cover or aluminum foil and place in the oven for 12 minutes. Remove the cover and bake for 25-30 minutes longer, until the casserole is puffed and browned. Serve at once with iced tea, coffee, or cold beer, with a green salad. This can be made in a roasting pan if the number of your guests so indicates.