– 2 lbs beef flank, [0.9 kg] of (flank, shank, chuck, or skirt) – 1 teaspoon salt, (more if needed) – ¼ teaspoon pepper (freshly-cracked, or ground), (more if needed) – 1 sprig of thyme, (optional) – 1 teaspoon oregano powder – 4 tablespoons vegetable oil, (peanut, soy or corn) – 1 large red onion, cut into slices – 3 cloves garlic, (crushed or sliced) – 1 cup diced carrot, (optional) – ½ cup red bell pepper, cut into cubes – 2 cup tomato, cut into large cubes – ½ tablespoon vinegar – 1 cup tomato sauce