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Roasted Butternut Squash & Caramelized Onion Casserole

Servings: ten to twelve.

Roasting the squash gives it a deep, sweet flavor and makes its thick skin easier to peel.


  • 2-1/2 lb. butternut squash
  • 1/4 cup olive oil; more for coating the squash
  • 4 cups sliced onion
  • 2 tsp. finely chopped garlic
  • 3 large eggs
  • 3 large egg yolks
  • 1-1/2 cups heavy cream
  • 1 Tbs. plus 1 tsp. chopped fresh thyme
  • 1/4 tsp. ground nutmeg
  • 1 Tbs. kosher salt
  • Freshly ground black pepper

Nutritional Information

  • Nutritional Sample Size based on twelve servings
  • Calories (kcal) : 240
  • Fat Calories (kcal): 180
  • Fat (g): 20
  • Saturated Fat (g): 10
  • Polyunsaturated Fat (g): 2
  • Monounsaturated Fat (g): 8
  • Cholesterol (mg): 160
  • Sodium (mg): 660
  • Carbohydrates (g): 12
  • Fiber (g): 2
  • Protein (g): 4


  • Heat the oven to 400°F. Rub the squash with olive oil, prick them with a knife in a few places, put them on a sheet pan, and roast until just tender when pierced with a knife, about 45 minutes. Let cool completely. Peel the squash, remove the seeds, and cut the flesh into slices 1/4 inch thick. Set aside.
  • Meanwhile, in a large sauté pan, heat 1/4 cup olive oil over medium-high heat. Add the onions; sauté, stirring occasionally, until they soften, about 5 minutes. Turn the heat to low; cook until the onions caramelize to a golden brown, about 20 minutes. Add the garlic; cook 1 minute. Put the onions in a colander in the sink to drain off the oil. Set aside.
  • Heat the oven to 350°F. Lightly grease a 9×13-inch casserole. In a large bowl, toss the caramelized onions with the squash slices; spread them out in the casserole.
  • In a medium bowl, mix the eggs, egg yolks, cream, thyme, nutmeg, salt, and pepper. Pour this over the squash and onions and massage well to distribute the custard mixture evenly. Cover the dish loosely with foil. Bake until the custard is set and a knife inserted comes out clean, about 55 minutes.


Rate or Review


  • garyknight | 11/19/2010

    This dish was SO good I feel compelled to share my own experience and offer a counter-opinion to the two-star rating. The squash and caramelized onion flavors melded wonderfully in the custard base, which was deliciously flavored with thyme and freshly grated nutmeg. The texture was perfect, too--tender slices of squash layered in a silken custard. This casserole was the star of a vegetable-dominated fall dinner party at which there were many other delicious foods. Plus, the cook said it was very easy to make.

  • dunnandrewj | 11/24/2009

    This recipe turned out very well, with a couple of caveats. I think that the previous reviewer is right about roasting the squash for a longer period so that it really is quite soft. I think I roasted mine nearly an hour. It will depend on the squash in question, and also your oven. My wife and I also agreed that an entire tablespoon of salt is too much. If I make it again, I will start with a teaspoon and sprinkle a bit more on top if necessary.One last thing, the grocery had no thyme that day, so I ended up using rosemary instead. The experiment was a great success, and I would recommend the substitution heartily

  • OrganicGirl98 | 03/18/2009

    I thought this was going to be so yummy but was very disappointed. I thought that the squash would continue to soften when baked with the other ingredients, but it didn't. So, nothing really melded- it was like squash and onions in custard. I may try it again and roast the squash to a softer consistency (even if I can't get nice, neat slices) and maybe even let the mixture sit for a while before baking.

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