Carefully cut the tops and bottoms off the squash, then cut in half and remove the seeds with a spoon. Place squash in the Multipurpose Steamer. Cover (it is okay if the lid does not completely close) and microwave on high for 12 min.
Melt butter in Sauté Pan over medium-high heat. Thinly slice celery. Add to pan and cook until soft, about 2 min.
Add seasoning and water; stir to combine. Add bread cubes and cook until bread is soft and liquid has absorbed, about 2 min.
Set oven to broil.
Carefully place cooked squash open side facing up on unlined Sheet Pan. Divide stuffing between squash halves. Broil 3—4 min, until crispy and browned.
Per serving (1/4 squash): Calories 180, Fat 4.5 g (Saturated 2 g, Trans 0.1 g), Cholesterol 10 mg, Sodium 230 mg, Carbohydrate 31 g (Fibre 4 g, Sugars 3 g), Protein 5 g.
For even more browning on the squash, brush with olive oil before broiling.