Grits Soufflé with Greens and Sweet Onion

Preheat an oven to 350°F. Lightly butter a 9-by-13-inch baking dish.

Stack 5 or 6 leaves of the greens on top of one another and roll up tightly. Cut on a diagonal into thin strips. Repeat with the remaining greens.

In a large fry pan over medium-high heat, melt the 4 Tbs. butter. Add the greens, sweet onion and garlic and cook, stirring occasionally, until the greens are wilted, about 10 minutes. Add the broth, reduce the heat to medium, cover partially and cook until the greens are tender, about 20 minutes more. Remove from the heat and let cool. Pour the greens into a sieve and drain well, pressing out any excess liquid. Transfer to a large bowl.

In a heavy saucepan over medium heat, bring the milk and cream to a simmer. Slowly stir in the grits, green onions and thyme, and season with salt and pepper. Reduce the heat to low, cover and cook, stirring frequently, until the grits are soft and the liquid is absorbed, about 20 minutes. Adjust the heat as needed to keep the grits cooking gently. Remove from the heat and stir in the cheddar cheese. Spoon the hot grits into the bowl with the greens and stir well to combine.

In a small bowl, lightly beat the egg yolks with a fork and quickly stir into the grits mixture. In a large bowl, using an electric mixer on high speed, beat the egg whites until stiff peaks form. Stir one-fourth of the beaten whites into the grits mixture. Using a rubber spatula, gently fold the lightened grits mixture into the remaining egg whites. Pour into the prepared dish. Sprinkle with the Parmigiano-Reggiano cheese. Bake until the soufflé is puffed and golden, about 40 minutes.