We like butternut squash roasted in chunks until they brown on the edges, or mashed with butter and salt, and especially in butternut squash risotto. Today I figured it was time for something else, and I wondered how difficult it would be to get the heavy mashed pulp to rise in a soufflé. I haven’t made a soufflé for eons, but I remember the high hat that puffs out of the dish before it falls a little, and the airy texture of the soufflé in your mouth. Surely this one will be different, still with a lighter texture than simple mashed squash, but not like a squash custard.
“Soufflés have the same kind of life as the ‘breath’ for which they are named. . . .”
My old Joy of Cooking (1967) has a whole section on soufflés—the one with eggplant looks yummy—but I have only ever made the traditional cheese soufflé. It starts with a thick white sauce, but that wouldn’t be necessary when you start with a thick mashed vegetable like squash or sweet potatoes. In the eggplant soufflé, there are breadcrumbs and chopped nuts mixed with the eggplant pulp, but a little milk is only recommended if the mixture seems “stiff.” It’s that point before you fold in the beaten egg whites that determines whether you need more moisture. The sweet potato soufflé uses a little applesauce for that moisture. If I need it, I will use a little milk, but I think I will try to infuse both moisture and lightness with eggs alone—4 eggs in total.
I’ll be mixing the squash, seasonings, and egg yolks in a food processor to a smooth puree, and then folding in the beaten egg whites by hand in a large bowl, but you could make it all by hand or with a hand mixer up to the egg white stage.
Savory Butternut Squash Soufflé
Recipe Timing: Timing this recipe depends on your method of cooking the squash. If you roast it in the oven, whole or peeled and in chunks, that will take time, but it could be done the day before, especially since it should cool before mixing with eggs. I cooked mine, whole, in the microwave for 10-16 minutes, so that expedited the process. With cooked squash, the rest of the recipe goes quickly, even with separating the eggs and whipping the egg whites.
Baking dish tips: Butter a 1 1/2 qt baking dish with high sides. Dust the bottom and sides of the dish with finely grated Parmesan cheese or flour. A dish with a smaller round circumference and higher sides works better than a low-sided larger dish, such as an 8 or 9 inch square baker.
Preheat oven to 350°
1 medium-large butternut squash, cooked—about 2 cups
1 tablespoon bacon fat
1 tablespoon finely grated Parmigiano Reggiano cheese
1/2 teaspoon dried thyme
1/2 teaspoon dried sage
1 teaspoon sea salt
1/4 teaspoon coarse ground black pepper
4 egg yolks
4 egg whites, stiffly beaten
- In bowl of food processor, combine squash, bacon fat, and seasonings to a puree. Taste for seasoning before adding egg yolks. Add egg yolks and pulse to blend.
- Transfer squash puree to large bowl. Fold in beaten egg whites with large spatula—a silicone spatula with a large paddle works better than a small one. Mine measures 5″ and is curved to fit the sides of bowls. Mine is blue, but you can see it in red here: http://www.amazon.com/KitchenAid-Silicone-Mixer-Spatula-Red/dp/B0095PC75C
- Pour mixture into prepared dish and bake at 350° for 40 minutes, then check to make sure the center has risen to the same height as the edges. If it is sunken in the middle, let it go for another 10 minutes.
- It does rise in the baking dish, but if you want a photo, take it quickly, because the whole thing sinks about an inch in a few minutes. I forgot to get one until it was too late.
The texture is lighter and airier than a squash custard (such as a pumpkin pie) but a little heavier than the traditional cheese soufflé made with white sauce. The edges/sides—if you dust the dish with grated cheese—have a nicely browned crust. A soufflé is a nice change for a traditional vegetable side dish. Think of all the ways you can work vegetables into one.