Step 1

Preheat oven to 375°F. Spray a 3-quart baking dish with cooking spray. Spread bread cubes evenly on large baking sheet. Bake 15 minutes, until golden brown and crisp, stirring halfway through; cool completely. Reduce oven temperature to 325°F.

Step 2

Melt butter in a 12-inch skillet over medium heat. Add onion and celery and cook until softened, about 6 minutes.

Step 3

Whisk together eggs, broth and heavy cream in a large bowl. Stir in bread, parsley, sage, salt, pepper and onion mixture. Pour into baking dish, cover with foil and bake 30 minutes. Remove foil and continue baking until golden brown, 20 to 25 minutes.