Preheat your oven to 325°F (160°C).
Season the steaks liberally with salt and pepper. Dip each piece on both sides in flour, then shake off any excess.
Heat the vegetable oil in a large, oven-safe skillet over medium-high heat. Sear the steak pieces on both sides until browned but not toasted, then remove from the skillet and set aside. Work in batches if necessary to avoid overcrowding the skillet.
Add the onion to the skillet and cook until translucent and slightly browned, around 5 minutes.
Slowly mix the beef broth, water, Worcestershire sauce, thyme, and rosemary. Bring the mixture to a boil and reduce the heat to medium-high once the gravy bubbles.
Place the browned steaks back into the skillet, spooning some gravy over the top. Cover with the lid and move the skillet to your preheated oven.
Allow to cook for 1 1/2 - 2 hours or until the gravy has thickened and the steak is tender. If it’s your first time making this recipe, you can use a meat thermometer to check for doneness.