Heat oil in a large, heavy-bottomed pan over high heat. Add stew meat and brown on all sides, stirring occasionally—about 8–10 minutes. Browning deepens the flavor of the final dish.

Add diced onion and bell pepper (if using). Cook until softened and fragrant, about 3–4 minutes.

Stir in tomato sauce or tomato, garlic powder (or fresh garlic), cumin, salt, and pepper. Mix well to coat the meat and vegetables in spices.

Sprinkle flour evenly over the mixture and toss well. Cook for 1–2 minutes to remove the raw flour taste.

Slowly pour in water or stock while stirring to prevent lumps. Bring to a boil, then reduce heat to low and cover. Let simmer for 1½ hours, stirring occasionally, until the meat is tender and the gravy is rich and thick.

Taste and adjust salt or pepper if needed. If the sauce is too thin, simmer uncovered for a few more minutes to reduce. If too thick, add a splash of broth.

Serve hot with warm flour tortillas for wrapping. Add rice or mashed potatoes on the side for a complete, hearty meal.