Season the meat with the garlic powder, cumin and salt and pepper to taste.
Heat the oil in a large skillet over medium high heat.
Add the meat and saute for 5 to 10 minutes, or until browned on all sides.
Add the flour, stirring well, and saute for 1 more minute. Gradually add the water, making sure to crush any flour lumps. Then add the onion and green bell pepper, reduce heat to low and simmer for 15 to 20 minutes. Season with salt and pepper to taste.