This is such a household favorite that I usually make a triple recipe, filling our poor little 18-quart Nesco oven to the very brim, and then freeze a bunch of it.
The recipe as I received it called for 1/2 teaspoon of cayenne (hah!). I replaced that with 3 items: roasted New Mexico chiles (Barkers if you like it really hot), chipotle powder, and chipotle puree. If you can't find some
or all of these ingredients, try to find some adobo sauce and use about 3 tablespoons of it. The chipotle puree is just pureed canned chipotles adobado (i.e., in adobo sauce), and it is the adobo that lends a delicious smoky flavor to the dish.
WARNING: IF YOU DO NOT HANDLE SPICY HOT FOOD WELL, replace some/all of the New Mexico peppers, chipotle powder, chipotle puree, and cayenne with something more suitable to your palate.