2 tablespoons avocado oil or olive oil

1 large yellow onion, chopped

1 pound lean ground beef

1 pound ground lamb

1/4 cup balsamic vinegar

3 cloves garlic, minced

1 tablespoon ground cinnamon

1 teaspoon dried oregano

1/2 teaspoon dried thyme

28 ounces crushed tomatoes

2 teaspoons salt

1 teaspoon black pepper

1 1/2 cups whole milk

1 cup heavy cream

1/2 stick salted butter

1/4 cup all-purpose flour

1/8 teaspoon ground nutmeg

1/2 teaspoon salt

1 teaspoon ground black pepper

1 1/2 cups Pecorino Romano or Parmesan cheese, divided

2 eggs

2/3 cup sheep yogurt or Greek yogurt

3/4 pound small shell pasta

Chopped fresh parsley (optional)