Zwiebelkuchen (Onion Cake)

Description:

Ingredients:

Dough:
2 tsp dry active yeast
2 tbsp melted butter
½ cup milk
¼ tsp sugar
½ tsp salt
1⅔ cups all-purpose flour

Topping:
1½ cups sour cream
1 egg
¼ tsp salt
⅛ tsp pepper
1 tbsp vegetable oil
1 onion
⅓ cup chopped bacon (optional)