Step 1 (8 minutes prep): Thinly slice the beef against the grain into bite-sized strips. Peel and dice the potatoes, carrots, parsnips, and celery root into small, uniform cubes (approximately 1 cm) to ensure quick cooking. Mince the onion and garlic. Roughly chop the fresh parsley.

Step 2 (5 minutes cook): Heat the olive oil in a large skillet or pot over medium-high heat for 1 minute. Add the beef strips and sear for 3-4 minutes until browned on all sides. Remove the beef from the skillet and set aside.

Step 3 (5 minutes cook): Add the diced onion to the same skillet and sauté for 2-3 minutes until softened. Add the minced garlic and sauté for another 1 minute until fragrant.

Step 4 (5 minutes cook): Add the diced potatoes, carrots, parsnips, and celery root to the skillet. Pour in the beef broth, add thyme, bay leaf, salt, and black pepper. Bring to a simmer, then cover and cook for 5-7 minutes, or until the vegetables are tender-crisp.

Step 5 (2 minutes cook): Return the seared beef to the skillet. Stir well and cook for another 2-3 minutes until the beef is heated through and flavors are combined.