1 to 1.5 pounds sirloin steak (or other steak), cut into thin 2-inch strips 1-2 Tablespoons oil 2 onions, sliced into 2-to-3-inch slices 1 large clove garlic, minced 2 tomatoes, diced 1 green bell pepper, sliced into thin, 2-inch slices 1 red bell pepper, sliced into thin, 2-inch slices 1 yellow bell... more