Onion Parmesan Gratin

Ingridients of Onion Parmesan Gratin:

• 2 lbs yellow onions
• 1/4 cup butter
• 1 pinch clove
• 1 pinch dried thyme
• salt and black pepper
• 2 egg yolks
• 1/4 cup whipping cream
• 1/2 cup grated parmesan cheese