Ingredients:
• 2 large eggs, room temperature, separated
• 200 g (about 1 1/2 cups) fresh butternut squash, peeled, seeded, and cut into 1-inch cubes (or one 12 oz package frozen winter squash, thawed and drained)
• 2 tablespoons unsalted butter, melted and slightly cooled (plus extra softened butter for coating dishes)
• 1 tablespoon granulated sugar
• 1/4 teaspoon kosher salt
• 1/8 teaspoon finely ground black pepper
• 1 to 2 tablespoon all-purpose flour (for dusting dishes)
Directions:
If using fresh squash:
• Place the cubes in a small saucepan, cover with cold water, and bring to a boil over medium-high heat.
• Cook until fork-tender, about 10 to 12 minutes.
• Drain thoroughly, let cool for 5 minutes, and puree in a food processor or blender until completely smooth.
If using frozen thawed squash:
• Puree until smooth, pressing through a fine-mesh sieve if it holds excess water.
• If you are using frozen squash, let it sit at the room temperature for 30 minutes.
Soufflé:
• Preheat the oven to 350°F (175°C) with a rack in the lower-middle position.
• Butter the interiors of two 8-ounce ramekins (or one 1/2-quart soufflé dish) using upward vertical strokes.
• Dust thoroughly with flour, tapping out any excess.
• Place the prepared dishes onto a rimmed baking sheet.
• In a medium bowl, whisk together the egg yolks, warm squash puree, melted butter, sugar, salt, and black pepper until uniform and glossy.
• In a clean, grease-free glass or metal bowl, beat the room-temperature egg whites on medium-high speed until stiff, glossy peaks form.
• Add one-fourth of the whipped whites into the squash base and stir briskly with a rubber spatula to lighten the mixture.
• Gently fold in the remaining whites in two batches, using a delicate under-and-over motion just until no white streaks remain. Avoid overmixing to keep the aeration intact.
• Divide the batter evenly between the prepared dishes, filling them about three-quarters full. Run the tip of your thumb around the inner rim of each dish to create a slight indentation (this promotes a straight, vertical rise).
• Bake until the soufflé is tall, golden, and slightly jiggly yet set in the center. Do not open the oven door during the first 20 minutes.
• Bring immediately to the table while fully puffed.
Individual ramekins:
• Bake for 22 to 26 minutes.
Single 1/2-quart dish:
• Bake for 45 to 50 minutes.
