1. Heat olive oil in pan and add beef shank seasoned with salt and pepper. Cook on both sides for a couple minutes. Add to pot. Do the same with the lamb after making crisscross cuts in the leg.
2. Dice up onion, slice carrots, parsnip, and celery, mince garlic. Add to pan when done with meat and cook for 5 minutes. Add to pot.
3. Add tomatoes, water, bay leaves, and mushrooms. Bring to boil.
4. Reduce heat and simmer for 3 hours, stirring occasionally, until you're happy with your stew.