Step 1

Preheat the oven to 350 degrees F (175 degrees C). Spray a 9x13-inch baking dish with cooking spray.

Step 2

Melt 2 tablespoons butter in a large skillet over medium heat. Add squash and onions and cook just until softened, 7 to 10 minutes. Don't overcook. Remove from heat and stir in chicken, Cheddar cheese, and crackers.

Step 3

Whisk mayonnaise, eggs, ranch dressing, and pepper together in a bowl. Gently stir into squash mixture and spread into the prepared baking dish.

Step 4

Combine stuffing mix and 1/2 cup melted butter in a separate bowl. Sprinkle over squash mixture, pressing down slightly.

Step 5

Bake in the preheated oven until set and lightly browned, 25 to 30 minutes. Garnish with chopped parsley.