1. Heat the oil in a large saucepot over medium-high heat. Add the mirepoix and a generous pinch each of salt and pepper. Cook, stirring occasionally, until tender, about 10 minutes. Add the turkey, generously season with salt and pepper, and cook, stirring to break the meat into tiny pieces, until cooked through, about 5 minutes.
2. Stir in the oregano and tomatoes and simmer until thickened, about 10 minutes. Meanwhile, cook the spaghetti according to the package's directions.
3. Remove the sauce from the heat and stir in the cream. Season to taste with salt and pepper. Transfer 3 cups sauce to an airtight container and refrigerate for the Three-Cheese Lasagna Hoagies. Mix the remaining sauce with the spaghetti and serve.
Tip: The sauce can be refrigerated in an airtight container for up to 3 days or frozen for up to 1 month.