Heat olive oil in a large soup pot, over medium-high heat
Once the oil is heated, add in the diced onions, carrots, celery, bell peppers, mushrooms, and the minced jalapeno pepper. Cook until the vegetables are wilted, about 5-7 minutes.
Add in the ground beef, minced garlic, desired salt and pepper, and cook until the beef is browned through, about 5 minutes.
Once beef has browned, add the oregano, cumin, chili powder, cayenne pepper, and tomato paste. Mix well and cook until the spices become fragrant, about 2 minutes.
Next, add in the crushed tomatoes and the beef broth, bring to a boil.
Reduce heat to medium and simmer for 15-20 minutes, stirring occasionally
Remove from heat and adjust seasonings, if necessary.
Garnish the chili (optional) with the diced red onion, the avocado slices, and the pinch of cilantro leaves