Kish Family Two-Bread Stuffing

INGREDIENTS

Unsalted butter, for greasing

1/4 cup

extra-virgin olive oil

4 cups

finely chopped yellow onions

4 cups

finely chopped celery

1/4 cup

finely chopped fresh sage

1 tbsp

grated garlic

12 cups

prepared cornbread, torn into 1-inch pieces (about 1 1/3 pounds)

day-old white sandwich bread loaves, torn into 1-inch pieces

3 tbsp

finely chopped fresh flat-leaf parsley

1 tbsp

kosher salt, plus more to taste

1/2 tsp

black pepper

6 cups

chicken stock or canned lower-sodium broth