White Bean Gratin Casserole

Prep Time 20 minutes
Cook Time 1 hour
Total Time 1 hour 20 minutes
Servings 4
Author Debi


  • 2 cups bread crumbs
  • 3 tablespoons finely chopped fresh herbs plus additional for garnish (see note below)
  • 3 tablespoons olive oil
  • 1 yellow onion chopped
  • 4 carrots sliced
  • 1 stalk celery sliced
  • ½ red pepper chopped into large pieces
  • 1 can white beans drained and rinsed
  • 1 ½ tablespoons olive oil or butter
  • 3 green onions chopped
  • 1 shallot finely chopped
  • ¾ cup milk
  • 1 tablespoon potato starch
  • ¼ cup shredded Parmesan plus 3 tablespoons for garnish
  • ¼ teaspoon Kosher salt
  • ½ teaspoon freshly ground black pepper
  • 1/3 cup sour cream


  1. Preheat oven to 375 degrees F. In a medium bowl, mix bread crumbs and fresh herbs. Drizzle with 3 tablespoons oil, and toss to coat. Spread coated bread crumbs out on a rimmed baking sheet, and bake, stirring frequently, until golden and crisp, about 5-8 minutes. Remove from oven, and set aside to cool.
  2. Heat oil in a large saucepan over medium-high heat, swirling to coat pan. Add chopped yellow onion to pan and sauté, stirring occasionally, until golden brown, about 20 minutes. If onions start to cook too quickly, add about ¼ cup water to slow the cooking and allow carmalization. Add carrots, celery, and red pepper to onions, and cook for 5 minutes. Add white beans to the pan, stir to combine, and heat through, about 3-5 more minutes. Remove veggies from pan, and place in a large bowl. Set aside.
  3. Wipe out the saucepan, and add 1 ½ tablespoon oil or butter. Once oil is hot, add shallot and green onion, and cook until softened, about 5 minutes. Add milk to shallot mixture, and heat through, without allowing to come to a boil, about 3-5 minutes. Sprinkle in potato starch, and stir to combine. Allow sauce to thicken, and stir in ¼ cup Parmesan cheese, salt, and pepper. Once cheese has melted, remove pan from heat, and stir in sour cream. Pour sauce over bean and veggie mixture, and stir gently to combine.
  4. Transfer the bean veggie mixture to a baking dish, and place, uncovered, in the 375 degree oven for 10-15 minutes to heat through. Carefully remove from the oven, and sprinkle bread crumb mixture over the top. Sprinkle with additional 3 tablespoons Parmesan cheese as well. Return to the oven and bake an additional 5 minutes.
  5. Remove from oven, and sprinkle casserole with additional fresh herbs to garnish. Serve hot.

Recipe Notes

Serves 4 as a main dish, or 6-8 as a side dish
As for the herb mixture in the casserole, I like to mix it up. I always have thyme and oregano growing in the garden, so I throw those in the mix. Chives, parsley, always good. In the summertime, basil is great! Fall, I’d throw in sage and rosemary.