While the base is baking, melt the butter with olive oil in a deep saucepan. Add the onion and garlic and sauté for 3-4 minutes. Add the minced meat and let it brown. Keep mixing.
Add the chopped tomato and pepper and stir. Start adding bone broth or water little by little. Let the sauce thicken. Add bay leaves.
Add salt, cinnamon, spearmint, oregano and let it simmer for 10 minutes so that the sauce thickens.
When the sauce is thick and creamy, remove it from heat. Add freshly ground pepper and let it cool down a bit. Now add 1 egg and stir well. Remove bay leaves.