Heat oil in large skillet over medium heat. Add beef and brown, breaking apart into small crumbles as it cooks, about 10 minutes. Drain any grease.
Add diced onion and bell pepper to same skillet and cook 2-3 minutes, until soft. Add pre-minced garlic and cook for another 30 seconds or so. Add beef back to the skillet and mix well.
While the beef is cooking add the remaining ingredients to a small mixing bowl using ½ the water or ½ cup. Whisk together until smooth. Add to the beef and vegetable mix in the skillet.
Cook over medium low heat for 10-15 minutes, until mixture has thickened to your desire. Use any remaining water as need to your desired consistency.