To a food processor, add onions, carrots, celery ribs, and garlic. Process for 30 seconds. Stop processor and remove lid. Use rubber spatula to scrape down sides of processor bowl. Lock lid back into place. Turn on processor and process until vegetables form puree and liquid is released, about 30 seconds. Stop processor. Remove lid and carefully remove processor blade (ask an adult for help).
In Dutch oven, combine pureed vegetables, ¼ oil, 2 bay leaves, ½ teaspoon pepper, and 1 teaspoon salt. Cook over medium heat, stirring occasionally with wooden spoon, until vegetables soften, about 20 minutes.
Then add to pot, beef, pork, and turkey. Use wooden a spoon to stir and break up meat into small pieces. Add 1 cup wine and cook, continuing to stir to break up meat, until meat is no longer pink, about 10 minutes.
Add 2 cups milk and increase heat to medium-high. Bring to rapid simmer (small bubbles should break constantly across surface of mixture) and cook until milk has reduced, about 15 minutes.
Stir in 2 cans crushed tomatoes, 1 cup chicken broth, and 1 tablespoon tamari and bring to simmer. Reduce heat to medium-low, and simmer, stirring occasionally, until liquid has reduced and sauce is thickened, about 1½ hours.
Stir in 3 tablespoons sliced butter and ⅛ teaspoon nutmeg until well combined. Turn off heat. Remove and discard bay leaves. Season with salt and pepper to taste.