Cook your spaghetti squash (if you haven't done so already). See notes below for different ways to cook spaghetti squash.
Preheat oven to 400 degrees F. Spray a 9 x 13″ baking dish with nonstick cooking spray.
In medium-sized skillet, ground the turkey over medium heat. Season with a few dashes of salt and pepper to taste. Use a wooden spoon to chop up the turkey until small pieces as it cooks. Transfer to large mixing bowl when done.
Drain and rinse the Shiratake noodles over the sink. Make sure to rinse thoroughly. Wipe the pan you cooked the turkey in (if needed) and spray the pan with nonstick cooking spray.
Sauté the noodles with salt and pepper on medium heat for about 5 minutes. This helps a ton with the flavor and texture of the noodles in the baked dish.
In the same large mixing bowl you added the turkey too, add the other ingredients for the bake, except the mozzarella: the cooked spaghetti squash strands, Shiratake noodles, cottage cheese, ricotta cheese, cream cheese, milk, artichoke hearts, baby spinach, garlic powder, onion powder, salt and ground pepper. (Note that you will either want the spaghetti squash or the turkey to be pretty warm for this part so that the spinach can wilt if you use fresh and the cream cheese can melt and mix evenly).
Once the ingredients are well combined, fold in the mozzarella.
Add the spaghetti squash mixture to the prepared baking dish.
Sprinkle with parmesan cheese, mozzarella cheese, and garlic powder.
Bake for about 15 minutes, or until the cheese is melted and bubbly.