Preheat your oven to 325°F (160°C). Pat the rump roast dry with paper towels. This helps create a better sear.

In a small bowl, mix together the olive oil, Worcestershire sauce, rosemary, thyme, garlic powder, onion powder, salt, and pepper. Rub this mixture all over the rump roast, ensuring it's evenly coated.

Heat a large, oven-safe skillet or Dutch oven over medium-high heat. Sear the rump roast on all sides until deeply browned, about 2-3 minutes per side. Remove the roast from the skillet and set aside.

Add the chopped carrots, celery, and onion to the same skillet. Sauté for about 5-7 minutes until they begin to soften. Add the minced garlic and cook for another minute until fragrant.

Pour in the beef broth and scrape up any browned bits from the bottom of the skillet. Bring to a simmer.

Place the seared rump roast on top of the vegetables in the skillet. If using a roasting pan, transfer the vegetables and broth to the pan, then place the roast on top.

Cover the skillet or roasting pan tightly with a lid or aluminum foil. Transfer to the preheated oven.

Roast for approximately 1.5 to 2 hours for medium-rare (130-135°F / 54-57°C), or 2 to 2.5 hours for medium (140-145°F / 60-63°C). Use a meat thermometer inserted into the thickest part of the roast to check for doneness. Adjust cooking time based on your desired level of doneness and the size of your roast.

Once cooked to your liking, remove the roast from the oven. Tent it loosely with foil and let it rest for at least 15-20 minutes before slicing. This allows the juices to redistribute, ensuring a tender and moist roast.

While the roast rests, you can thicken the pan juices into a gravy if desired. Strain the juices, skim off excess fat, and simmer in a saucepan until reduced. You can thicken with a cornstarch slurry (1 tbsp cornstarch mixed with 2 tbsp cold water) if needed.