In a large enameled cast-iron casserole, melt 1 tablespoon of the butter in 1 tablespoon of the oil. Season the pork with salt and pepper. Add one-third of the pork to the casserole and cook over moderately high heat, stirring occasionally, until well browned, about 8 minutes. Transfer the pork to a baking sheet. Repeat in 2 more batches with the remaining butter, oil and pork.
Add the bacon to the pot and cook until golden; add to the pork. Add the onion and garlic to the pot; cook over moderate heat, stirring, until golden and softened, 5 minutes. Add the pork, bacon, cider, stock and bay leaves to the casserole; bring to a simmer. Cover and simmer gently until the pork is tender, 2½ hours. Discard the bay leaves.
In a small bowl, whisk the cornstarch with 1/4 cup of water. Add the cornstarch mixture and the cream to the stew and simmer until the liquid is thickened, about 5 minutes. Stir in the mustard and sage and season with salt and pepper.
Heat oil in large pot. Season pork shoulder pieces with salt and pepper and cook over medium heat until meat is browned on all sides, 5 to 7 minutes.
Add "dry" items--the garlic, serrano peppers and onions, and cook until onion has softened, another 5 to 7 minutes. Then add chili pepper, stir to coat ingredients, and cook a minute more.
Adjust heat to low and add remaining ingredients--the chicken stock, kidney beans, diced tomatoes and tomato paste and stir to combine. Cover and let simmer for 5 hours, stirring occasionally, until flavors have had plenty of time to blend. Enjoy.
Chili can be garnished with shredded cheese, sour cream, avocado slices or tortilla chips.
This recipe can also be made in a crockpot with all ingredients cooked on low for 8 - 9 hours.