In a skillet, sauté onions, bell pepper, green onions, bay leaf, garlic, and parsley in butter and olive oil for 5 minutes. Add cornstarch and thicken for about a minute. Add crawfish tails, white wine, 1 cup of water and stir. Add white pepper, black pepper, cayenne pepper, and Tony. Cook on low for about 15 minutes. Add half and half then cook on very low for 5 more minutes. Set aside and keep warm.