Place the oven rack in the center position, preheat oven to 400 degrees Fahrenheit. Line a large baking sheet with foil.
Cut 3 pounds spaghetti squash into 1-inch wide rings, scoop out the seeds, and transfer to a baking sheet. Lightly brush the rings with 2 tablespoons olive oil and sprinkle with salt to taste on both sides.
Roast the squash until tender, about 35 to 40 minutes. Cool slightly and then use a fork to remove and separate the strands.
Turkey Bolognese
Heat 2 tablespoons olive oil over medium-high heat in a large heavy saucepan. Add 1 pound ground turkey and cook the meat, stirring occasionally, about 5 to 7 minutes. Transfer the cooked meat to a medium-sized bowl.
Turn the heat down to medium-low. Add ½ cup diced carrots and ½ cup minced yellow onion and cook until the vegetables begin to soften, 4 to 5 minutes. Add 1 teaspoon minced garlic and cook for 1 minute. Add 1 cup sliced brown mushrooms cook for 2 minutes. Add 3 tablespoons tomato paste and cook for 1 minute.
Add the browned meat, 1 (28-ounce) can crushed tomatoes, ¼ teaspoon dried oregano, 1 teaspoon kosher salt, and ¼ teaspoon black pepper then stir well to combine.
Simmer the sauce over medium-low heat. Cover the pan, leaving a small opening for steam to escape.
Cook sauce until the meat is tender and the flavors have melded, at least 30 minutes to 1 hour, stirring every 10 minutes. Add some water if the sauce starts to look dry.
Top the roasted spaghetti squash with turkey bolognese sauce and garnish with ½ cup grated parmesan cheese and ¼ cup chopped Italian parsley leaves.