Prep the squash: Preheat your oven to 400°F (205°C).
Halve the spaghetti squash lengthwise and scoop out the seeds. Drizzle each half with 1 tablespoon olive oil total and a pinch of salt and pepper.
Roast: Place the halves cut side down on a parchment-lined baking sheet. Roast for 30–40 minutes, until the flesh is tender and strands pull away easily with a fork.
Set aside to cool slightly.
Make the turkey filling: While the squash roasts, heat 1 tablespoon olive oil in a large skillet over medium heat. Add the onion and cook 3–4 minutes until softened. Stir in garlic and cook 30 seconds.
Brown the turkey: Add ground turkey and cook, breaking it up with a spatula, until no longer pink, about 5–6 minutes.
Sprinkle in chili powder, cumin, smoked paprika, oregano, salt, pepper, and cayenne if using. Stir to coat.
Sauce it up: Pour in tomato sauce and broth. Simmer 2–3 minutes until slightly thickened.
Taste and adjust salt or heat as needed.
Shred the squash: Flip the roasted squash halves and use a fork to pull the strands toward the center, leaving a little border so the shells stay sturdy. Transfer most strands to a bowl.
Combine: Add half the salsa to the bowl of squash strands. Fold in the turkey mixture and half the cheese.
Stir gently to combine and keep the strands intact.
Fill the boats: Spoon the mixture evenly back into the squash shells. Top with remaining cheese.
Final bake: Return to the oven for 8–10 minutes, until the cheese is melted and bubbly. Broil 1–2 minutes if you like a golden top.
Finish and serve: Drizzle with remaining salsa.
Add avocado, dollops of sour cream, a sprinkle of cilantro, and a squeeze of lime. Serve hot.