Slow Cooked Steak Diane Casserole Nicky CorbishleyMarch 31, 2020 89 Kitchen Sanctuary Slow Cooked Steak Diane Casserole - a great make-ahead meal, just the thing if you're feeding a crowd! I'll show you how you can cook in the oven, on the hob or in the slow cooker.Slow Cooked Steak Diane CasseroleSee the full directions on my site