How to Make It
Toast the bread in a toaster oven until golden. Cut into 1 1/2-inch pieces and transfer to a large bowl. In a large, deep skillet, melt the 4 tablespoons of butter in the olive oil. Add the onion, celery and leeks and season with salt and pepper. Cook over moderate heat, stirring occasionally, until the vegetables are softened, about 10 minutes. Stir in the ham, sage and thyme. Add the mixture to the pieces of toast along with the cheese and toss well. Add the stock, season with salt and pepper and stir until the stock is absorbed.
Light a gas grill and set the burners to moderate (about 375°). Stack three 9-by-12-by-3-inch disposable foil pans and butter the inside of the top one. Spoon the stuffing into the pan. Cover with foil and grill with the lid closed for 30 minutes. Remove the foil and continue to grill with the lid closed for 45 minutes, until the stuffing is sizzling around the edge and the top is very crisp. Alternatively, bake the stuffing in the oven in a 9-by-13-inch glass or ceramic baking dish. Serve hot.