In a large pot over medium heat, add 1 tablespoon of olive oil and duck or bacon fat (if using). If not using duck or bacon fat, add in another tablespoons of olive oil.
Once hot, add in the ground turkey and cook until no longer pink, about 3-5 minutes. Remove from heat and set aside, leaving any juices in the pot.
Add the carrot, celery, and onion into the pot. Cook until tender, about 5 minutes, and stirring occasionally.
Add the ground meat back into the pot, along with the garlic, basil, sage, red pepper flakes, oregano, and bay leaf. Cook for 1 more minute.
Reduce the heat to medium-low.
Stir in the milk and cook for 3-5 minutes or until most of the loose liquid is evaporated.
Add in the wine and repeat, cooking 3-5 minutes or until most of the loose liquid has evaporated.
Add in the spaghetti sauce and 1/4 cup chicken stock. If you plan to cook for more than 2 1/2 hours, add in the full 1/2 cup of chicken stock.
Reduce the heat to low. Cover the pot with a lid and simmer for at least an hour or up to 5 hours. If the sauce appears too thick, add in more chicken stock 1/4 cup at a time.
Remove from heat and serve with your choice of pasta and sides.
