Step 1

Preheat oven to 400 degrees F. Line a rimmed baking sheet with foil. Place squash, cut-side down, on the prepared baking sheet; bake until tender, 35 to 45 minutes. Turn the squash halves over. When cool enough to handle, use a fork to scrape out the strands of flesh. Set the squash and the squash shells aside. Reduce oven temperature to 350 degrees F.

Step 2

Meanwhile, heat oil in a large nonstick skillet over medium heat. Add carrot, celery, onion and garlic and cook, stirring often, until softened, 8 to 10 minutes.

Step 3

Reduce heat to low. Stir in chicken, Neufchâtel, hot sauce, milk and celery seeds and cook, stirring, until the cheese is completely melted and the ingredients are combined, 1 to 2 minutes. Add the reserved squash and toss to combine.

Step 4

Divide the chicken mixture between the squash halves. Place on a baking sheet and bake, uncovered, until heated through, about 20 minutes. To serve, cut each squash half in half crosswise. Sprinkle each serving with 1 tablespoon blue cheese and 1 tablespoon scallions.