Preheat your oven to 325°F (160°C).
Cut the beef round steak into serving-sized pieces and pound them to tenderize.
Season the flour with salt and pepper, then dredge the steak pieces in the flour mixture.
Heat the vegetable oil in a large skillet over medium-high heat.
Brown the steak pieces on both sides, about 3-4 minutes per side.
Remove the steak from the skillet and set aside.
In the same skillet, add the chopped onion and green bell pepper, sauté until softened.
Stir in the diced tomatoes, Worcestershire sauce, and garlic powder.
Return the browned steak to the skillet, spoon the sauce over the top.
Cover the skillet and transfer it to the preheated oven. Bake for 1 hour.