1 tablespoon canola oil
1 medium onion, finely diced
3 stalks celery, finely diced
1/3 cup kielbasa
6 cups coarsely crumbled cornbread
2 tablespoons chopped fresh sage (or 1 teaspoon dried)
3 cups hot reduced-sodium chicken broth
Coarse salt and ground pepper
2 tablespoons margarine, plus more for dish

Preheat oven to 350 degrees. Heat oil in a 12-inch skillet over medium heat. Add onion and celery; cook, stirring occasionally, until onion is translucent, 6 to 8 minutes. Add kielbasa; cook, stirring, until beginning to brown, about 4 minutes.
In a large bowl, combine onion mixture, cornbread, and sage.
Pour broth over mixture; stir just until combined. Season with salt and pepper. Transfer to a greased 1 1/2-quart shallow baking dish.
Dot with margarine. Bake until golden brown on top and crisp around edges, 40 to 45 minutes.