Cook spaghetti squash however you like. You can roast it cut-side down like Martha Stewart, which is my preferred method. Or just poke it a few times and microwave the whole thing for 5-8 minutes, which is what I did for this! While it's cooking, continue with the rest of the steps.
Heat a heavy-bottomed shallow pan over medium-high heat. Spray with cooking spray, then add diced onions and a sprinkle of kosher salt. Cook for 3-4 minutes, until tender.
Add ground turkey and seasonings. Once the ground turkey is chopped and cooked through, add more salt to taste if needed.
Add drained tomatoes and garlic. Cook for another 3 minutes.
Add the chopped spinach and mix it in, letting it cook for a couple of minutes to wilt and fully incorporate.
Stir in 400g of cauliflower cream sauce and the fresh basil.
Carefully cut the squash in half lengthwise, then scoop out the seeds and insides with an ice cream scoop, careful not to pull out too much of the good stuff.
Using a fork, scrape the squash into strings to loosen them from the skin and add them to the ground turkey mixture. Mix it all together well in the pan with tongs.
If you're using an oven-safe pan, smooth the top of the mixture and top with mozzarella. Bake at 350°F for 15-20 minutes till the top is melty and bubbly. If you want it to brown a bit like mine, broil for an additional 3-5 minutes. But watch it closely so it doesn't burn!
If it's not an oven-safe pan, transfer the mixture to a casserole dish, top with cheese, and bake as described.