Gorgonzola Soufflé with Rapini

THE RAPINI: In a large saucepan, bring 2 cups of water to a boil. Meanwhile, trim an inch from the stems of the rapini. Rinse and drain what remains.

Add ½ teaspoon salt to the boiling water along with the rapini. Cover and cook over medium heat until the stems become tender, about 6 to 8 minutes. Drain and rinse under cold running water. Drain again and chop coarsely.

In a large skillet over medium-low heat, heat the olive oil. Add the onion and garlic, cooking until softened. Increase the heat to medium, and add the rapini. Cook, stirring frequently, until the rapini is heated through, about 5 minutes. Season with salt and pepper to taste. Set aside.

THE GORGONZOLA SOUFFLÉ: Position a rack in the bottom third of the oven. Heat the oven to 425°F.

Using about 1 tablespoon of the butter, generously grease the bottom and sides of a 1-quart soufflé dish. Add the walnuts, shaking the dish to coat evenly. Set aside.

In a small saucepan, bring the milk to a simmer. Remove from the heat.

In a medium saucepan over low heat, melt the remaining 2 tablespoons of butter. Once the butter has melted, whisk in the flour to make a roux. Stirring occasionally, cook the roux until the smell of raw flour disappears, about 3 to 5 minutes. Do not allow the roux to brown.

Pouring in a steady stream, add the heated milk, whisking constantly as you go. Continue cooking and whisking the roux until it becomes smooth and thick, about 3 to 5 minutes. Remove from the heat.

Stir in the egg yolks, mustard, and sea salt. When these have been incorporated, stir in the Gorgonzola. Continue to stir until the mixture becomes reasonably smooth (a few small lumps are okay). Cover and set aside. (Note: This mixture can be prepared up to 2 hours in advance.)

Beat the egg whites just until stiff peaks form. Fold about one-quarter into the cheese sauce. Repeat until all the whites have been incorporated. Transfer the result to the prepared soufflé dish. (Note: It will not fill the dish.)

Place the soufflé dish on the oven rack and immediately reduce the oven temperature to 400°F. Bake until the top of the soufflé has puffed up and turned golden brown, about 25 minutes. (Note: The center should move only slightly when the dish is jiggled.)

A few minutes before the soufflé is done, stir the balsamic vinegar into the rapini and begin a gentle reheating.

When the soufflé is done, divide the rapini among four plates. Add a serving of the soufflé to each. Serve immediately.