Season veal with salt and pepper. Brown veal in batches in butter and oil in large pot over medium heat. Remove from pot.
Split vanilla beans lengthwise. Scrape out seeds; reserve seeds.
Add vanilla pods, carrots, celery, lemongrass, chili peppers, garlic and thyme to pot; sauté 1 minute. Stir in stock, deglazing pot; bring to a boil. Return veal to pot. Reduce heat; cover tightly and simmer 1 to 1-1/4 hours or until veal is fork-tender.
Meanwhile blanch peas 1 minute or until tender; refresh in ice water. Repeat with mushrooms (2 minutes), then with onions (4 minutes). Set vegetables aside.
Remove veal from pot with slotted spoon. Strain cooking liquid into a clean pot; press and discard solids. Cook liquid until reduced by about 1/4, to medium consistency. Whisk in coconut milk, crème fraîche, lime juice, plenty of black pepper and reserved vanilla seeds. Bring to a simmer. Return veal to pot; add blanched vegetables. Heat through. Keep warm.
Ladle 1-1/2 cups stew into bowl. Garnish with cilantro, if desired.