Heat olive oil in a large skillet over medium heat.
Add diced onion and cook for 3 minutes until softened.
Add minced garlic and cook for 1 minute until fragrant.
Add ground beef to the skillet and cook, breaking it apart with a spoon, until browned and cooked through, about 6-8 minutes.
Drain any excess fat from the skillet.
Add diced red bell pepper and sliced mushrooms to the skillet and cook for 4 minutes until vegetables are tender.
Stir in ground cumin, smoked paprika, chili powder, salt, and black pepper. Cook for 1 minute to toast the spices.
Add drained diced tomatoes and beef broth to the skillet. Stir to combine and bring to a simmer.
Reduce heat to low and cook for 5 minutes to allow flavors to meld.
Stir in chopped fresh spinach and cook for 1-2 minutes until wilted.
Remove from heat and serve warm.