Preheat the oven to 375°F (190°C). Generously butter a 9-inch round baking dish, coating the bottom and sides.

Melt 4 tablespoons butter in a medium saucepan over medium heat. Whisk in 3 tablespoons flour and cook, whisking constantly, for 1 minute.

Slowly pour in 1 cup whole milk while whisking. Cook 3–4 minutes, whisking, until the sauce thickens enough to coat the back of a spoon. Remove from heat and let cool slightly.

Pulse 3 cups corn kernels in a food processor until about half are broken down. Stir the corn and 1/2 cup grated cheddar (if using) into the warm sauce.

When the mixture is warm (not hot), whisk in 4 egg yolks one at a time until fully incorporated.

Season the mixture with 1 teaspoon salt, 1/4 teaspoon white pepper, 1/4 teaspoon nutmeg, and 2 tablespoons chopped herbs if using. Set aside.

In a clean bowl, beat 5 egg whites with an electric mixer until stiff peaks form, about 4–5 minutes.

Fold one-third of the beaten egg whites into the corn mixture to lighten it, then gently fold in the remaining whites until no white streaks remain.

Pour the batter into the prepared dish, smooth the top, and place the dish on a baking sheet.

Bake at 375°F (190°C) for 35–40 minutes, until the souffle is puffed, golden brown, and the center jiggles slightly when the dish is gently shaken.

Remove from the oven, let rest 2 minutes to set, and serve immediately for the best rise and texture.