I Have Never Eaten Such Delicious Dinner! Healthy And Easy Mushroom And Potato Casserole!

Ingredients:

800 g potatoes
400 g mushrooms
200 g bell peppers
100 g mozzarella cheese
200 ml greek yogurt
100 ml milk
4 eggs
1 large onion
3 tbsp olive oil
2 tbsp all purpose flour
Salt, black pepper and thyme