Preheat oven to 400°F (200°C). Brush squash halves with 1 teaspoon oil, season with 1 teaspoon salt and 1/2 teaspoon pepper. Roast cut side down for 30 minutes, then flip and set aside.
In a large skillet, heat 1 tablespoon olive oil. Cook ground turkey with 1 teaspoon salt and 1/2 teaspoon pepper until no longer pink, about 6 minutes. Transfer to a plate.
Cook onion and celery until softened, about 5 minutes. Add garlic and cook 30 seconds. Stir in remaining salt, quinoa, and water. Bring to boil, then simmer covered for 15-20 minutes until fluffy.
Return turkey to pan, add apple, cranberries, sage, and thyme. Warm through, season to taste.
Divide filling among squash halves. Bake for 10-12 minutes to brown tops. Serve warm.
Notes
Ensure quinoa is rinsed before cooking for best results.