Sometimes called “Japanese pumpkin,” kabocha is a hardy winter squash with low water content and a tough exterior protecting fragrant and sweet deep-orange flesh. You can usually find it at produce markets, but for this savory gluten-free soufflé you can substitute Hubbard, pumpkin, or butternut squash. Be sure to drain the pumpkin or squash puree in a cheesecloth- or paper towel–lined strainer for 30 minutes before using.
Kabocha Squash Soufflé
- 1-1/2 cups whole milk
- 2 sprigs fresh thyme
- 3 1/2-inch slices white onion
- 2 whole cloves
- 3 tablespoons unsalted butter, plus more for greasing
- 1/4 cup finely grated Parmesan cheese
- 1 cup Roasted, Pureed Kabocha Squash (recipe below), drained at least 30 minutes
- Kosher salt and freshly ground pepper
- 3 tablespoons white rice flour
- 4 egg yolks
- 1 cup grated Gruyère cheese
- 1/2 teaspoon ground sage, or 1 teaspoon minced fresh sage leaves
- 6 egg whites, at room temperature
In a small saucepan, bring the milk, thyme, onion, and cloves to a simmer. Turn off the heat and let steep for 15 minutes
Butter a 12-cup gratin dish or a 10-cup soufflé dish, which is traditionally deeper (a wider dish will rise less but will cook faster). Sprinkle the Parmesan along the inner sides of the dish.
Place the drained squash in a large bowl. Season to taste with salt and pepper, being aware that the Gruyère will also add saltiness. Set aside.
Preheat the oven to 400°F. In a small saucepan over low heat, melt the butter, making sure it doesn’t brown. Whisk in the rice flour and cook over medium-low heat, stirring often, until the mixture begins to turn golden brown.
Strain the milk, discarding the solids, whisk into the flour mixture, and cook, stirring constantly, until the mixture just begins to thicken, about 1 minute. Pour into the bowl of squash and mix well. Slowly add the egg yolks, two at a time, stirring constantly. Add the Gruyère and sage and mix well.
In the bowl of a stand mixer with a whisk attachment or by hand, whisk the egg whites with a pinch of salt until stiff peaks form. Gently fold into the squash mixture in thirds, making sure the whites are fully incorporated and no white streaks remain. Pour into the prepared dish.
Place the dish in the center of the oven, immediately lower the temperature to 375°F, and bake until the soufflé is golden brown on top and firm around the sides, about 30 minutes.
If you want a more solid center or you’re using a deeper dish, bake for about 5 minutes longer. Try to keep the oven door closed to allow the soufflé to rise to its full potential. Serve immediately.
Roasted, Pureed Kabocha Squash
- 1 medium kabocha squash (about 3 pounds)
- Safflower oil or canola oil
Preheat the oven to 375°F. Cut the squash in half lengthwise and scoop out the seeds and stringy flesh. Lightly brush the cut sides with oil, place cutside down on a rimmed baking sheet, and roast until the flesh is soft and easily pierced with a fork, about 45 minutes. Let rest on the baking sheet until cool enough to handle. Using a metal soupspoon, scoop out the flesh and place it in a food processor. Puree until completely smooth.
To use the puree in the Kabocha Squash Soufflé, drain the pureed squash in a cheesecloth- or paper towel–lined colander or a very fine mesh strainer for at least 30 minutes and up to 1 hour to release excess liquid before using.