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 2 tablespoons 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.
