Start by heating the extra virgin olive oil in a large skillet over medium heat.

Add the chopped onions and diced bell peppers to the skillet. Sauté for about 5 minutes until softened, adding minced garlic during the last minute.

Raise the heat to medium-high, and introduce the lean ground beef. Cook until browned, breaking it apart for approximately 8 minutes.

If there's excess fat, drain it, and mix in the cumin, dried oregano, salt, and pepper. Cook for an additional 2 minutes.

Stir in the diced tomatoes along with their juices, mixing thoroughly. Reduce heat to low and let simmer uncovered for around 10 minutes.

Taste and adjust seasoning if needed before serving. Optional: serve with warm tortillas or over rice.