▢ Heat olive oil in a large pot. Cut beef into 1 inch (2.5 cm) cubes and brown in oil. ▢ Dice the onion and add to browning beef. Add the stock and bring to a boil, then lower the heat, cover, and let simmer for about 30 minutes. ▢ Peel and cut the rutabaga and celery root into 1 inch (2.5 cm) cubes. Add to the pot, cover, and continue simmering for another 30 minutes. ▢ Peel and chop the rest of the vegetables into 1 inch (2.5 cm) cubes and add to the pot. Slice the leek into rings. Cover and continue simmering for about 20 minutes. Stir as little as possible. ▢ Top with fresh parsley.