Preheat a large dutch oven or other type of heavy large pot over medium high heat. Add the oil and lard and bring up to temperature. Reduce heat to lowest setting and and prepare the meat(s).
Mix the black pepper, salt, cumin, onion powder, chili powder and cinnamon together and reserve in a bowl. Use 1/3 of the southwestern spice mixture on the chuck steak, 1/3 on the ground chuck and 1/3 on the vegetables when the recipe calls for it.
Roughly measure out the chuck steak. If you are a little over, that's okay. Cut the chuck steak into 3/4-inch cubes. Discard excess fat or cartilage while prepping.
Roughly measure out the ground chuck to match a 50:50 ratio with the chuck steak.
In a large mixing bowl assertively season the chuck steak separately from the ground chuck. You will cook the meat(s) separately to build layers of flavor or fond. Once the chuck steak is seasoned, add half of the masa harina and toss to coat well.
Bring the temperature of the prepared dutch oven or large pot back up to medium-high heat. Add the chuck steak in a single layer across the bottom of the pot and leave without stirring to brown the meat. Cook the meat until you can see a brown crust has formed on the cooking side of the beef. Once it has a nice browned coating turn the meat to cook all sides. This may take a little while, but it is how you build layers of flavor. While the meat is cooking, you can prep the other ingredients to get them ready to add when it is time.
Repeat the same process as mentioned above with the ground chuck steak. Be sure to toss with the masa harina. After all of the chuck steak has been cooked and reserved in another dish, cook all of the ground chuck in the same manner. Once all the ground chuck is cooked, remove and reserve with the chuck steak.
Dice the onions, chilies and garlic to add once all of the meat has been cooked. Stir to incorporate and cook over the same medium-high heat. Add the seasonings with the addition of oregano, tomato paste and chopped tomato. Stir and cook for about 8 minutes, being careful not to burn. If you need to lower the heat, remove the pot from the burner and allow to cool slightly before returning to the flame or element. Cooking the vegetables and spices will help add another layer of flavor.
Once the vegetables are just about cooked and soft, add 2-12oz bottles of amber beer. Stir to mix in while deglazing the fond from the bottom of the pot. This will release all the layered flavors built up to this point. Cook the chili for 8 minutes to allow the beer to release the alcohol and reduce to concentrate flavors. Add the meat back to the pot along with any accumulated juices.
Add the chicken stock and bring to just to a boil. Reduce the heat to medium-low and place a lid on the chili. Allow the chili to steep and cook like this for for 1-2 hours to allow the flavors to marry and for the chuck steak to become tender. After 1 hour check the tenderness of the chuck steak. It should be soft enough to melt in your mouth. Depending on the quality of the chuck steak this is the last thing you are looking for to determine if it is ready to eat. This might take 2-2.5 hours so plan accordingly.
Just before service, stir in the bittersweet chocolate. Stir until it has fully melted and incorporated. The chili is now ready to eat.