Another vote for smoked brisket. Actually a lot more votes. I won the office chili cook off a couple months back. Used about 25% brisket to 75% 85/15 ground beef. There were nine chilis and 26 votes altogether. I got 17 votes, three others got the rest of the votes, and five people got zero votes. I tried them all and they were all good enough to eat, but only a couple were great. Using dried chilis makes most of the difference to me. I used ancho, guajillo, and chili de arbol. Seed them and toast them in a dry skillet then soak them in hot water about ten minutes. Blend them with some of the soaking liquid to make a paste then fry that paste until it darkens a bit before adding onions and meat.
Similar to what I do but I use beef stock instead of water.
Re hydrated chilies make a very rich flavorful chili.
Has anyone used beef tenderloin? Would the tenderness of the cut be appealing?
I know it doesn’t have the most flavor but it may pick up the peppers flavor during a slow cook.