Sliced avocado, for garnish
In a large stock pot, heat olive oil over medium-high heat.
Add onion and sauté for about 8 minutes, stirring occasionally.
Add green peppers and serrano peppers and sauté for an additional 5–6 minutes.
Add garlic and cauliflower and continue to sauté for 3–4 more minutes.
Move vegetables aside in the stock pot.
Cook beef in the center until browned and almost cooked through.
Add thyme, cayenne pepper, salt, and pepper to the beef and stir.
Add tomatoes and turn heat to high.
Stir so tomatoes are well incorporated.
Add beef broth and bring to a boil.
Simmer for about 10–15 minutes and serve with avocado slices.