Spinach and Bacon Soufflé
- 1 tsp. olive oil
- 3 bacon slices, cut into 1/2-inch squares
- 1/3 cup grated Parmigiano-Reggiano cheese
- 2 Tbs. unsalted butter
- 1 yellow onion, diced
- 6 Tbs. all-purpose flour
- 2 cups milk
- 5 egg yolks
- Salt and freshly ground pepper, to taste
- 6 egg whites, at room temperature
- 1 1/2 cups lightly packed shredded Gruyère cheese
- 2 cups lightly packed baby spinach leaves or
tender larger leaves, torn into pieces, carefully
rinsed and dried
Meanwhile, preheat an oven to 450°F. Butter a 2-quart soufflé dish and dust with half of the Parmigiano-Reggiano. Measure out a sheet of aluminum foil long enough to encircle the soufflé dish with an extra 2 inches left over and fold it in half lengthwise. Butter one side of the foil. Wrap it, butter side in, around the soufflé dish, positioning it so that it stands 2 inches above the rim of the dish. Secure in place with kitchen string.
In a saucepan over medium-low heat, melt the 2 Tbs. butter. Add the onion and sauté, stirring occasionally, until soft, about 10 minutes. Stir in the flour and cook, stirring constantly, for 2 minutes, allowing the mixture to bubble. Meanwhile, in a saucepan over medium heat, bring the milk to just below a boil. Remove the onion mixture from the heat and gradually whisk in the hot milk. Return to medium-low heat and cook, stirring constantly with a wooden spoon, until thick and smooth, 2 to 3 minutes. Transfer to a large bowl and stir in the bacon. Add the egg yolks one at a time, stirring well after each addition. Season with salt and pepper and set aside.
In a bowl, using a balloon whisk, beat the egg whites until stiff peaks form. Using a rubber spatula, fold half of the whites into the yolk mixture to lighten it. Top with the Gruyère, the remaining whites and the spinach and fold in just until no white drifts remain. Do not overmix. Pour into the prepared soufflé dish. Sprinkle the remaining Parmigiano-Reggiano evenly over the top.
Bake until the top is golden and the center no longer quivers when the dish is shaken, 35 to 45 minutes. Remove the foil and serve immediately.