Preheat oven to 400 degrees.
Add oil and butter to a hot casserole. Sweat carrots, onions, and celery and cook until soft, but without color. Remove from heat and add marjoram and thyme. In a bowl combine focaccia, vegetables, hot stock, cider, and chestnuts. Season with salt and pepper to taste. Mix well. Place in covered baking dish and bake for 30 minutes