Vegan Sauerkraut Casserole

Name: Vegan Sauerkraut Casserole
Ingredients: * 1/4 white onion, diced; * 2 stalk celery, chopped; * 2 small carrot, chopped; * 1 medium sweet potato, diced; * 8oz mushroom; * 1/2 cup veggie broth; * 3-4 seitan sausage (optional); * 1 tsp caraway seed; * 1/2 tsp fennel seed; * 1 apple (braeburn); * 1 cup white wine; * 2 1/2 cup sauerkraut; * 3 tb apple cider vinegar; * 1 tb spicy brown mustard; * 1/4 tsp pepper; * 1/4 tsp salt; * 2-3 potato, sliced thinly to top or 1/2 bag frozen hash brown