Preheat the oven to 375°F (190°C). Grease four 6-ounce ramekins with butter and dust with a light coating of flour or grated Parmesan to prevent sticking.

In a medium saucepan over medium heat, melt the 2 tablespoons of butter. Add the flour and whisk continuously for about 1–2 minutes to form a roux, ensuring it doesn't brown.

Gradually pour in the milk, whisking constantly to achieve a smooth mixture. Continue cooking until the mixture thickens into a béchamel sauce, approximately 3–5 minutes. Remove from heat.

Stir in the grated Parmesan cheese, ground black pepper, salt, and nutmeg (if using) until well combined. Let the mixture cool slightly.

Once the mixture has cooled, add the egg yolks one at a time, whisking thoroughly after each addition until fully incorporated.

In a separate clean bowl, beat the egg whites with an electric mixer until stiff peaks form.

Gently fold a third of the beaten egg whites into the cheese mixture to lighten it. Then, carefully fold in the remaining egg whites until just combined, being cautious not to deflate the mixture.

Divide the soufflé batter evenly among the prepared ramekins. Run your thumb around the inside edge of each ramekin to help the soufflés rise evenly.

Place the ramekins on a baking sheet and bake in the preheated oven for 20–25 minutes, or until the soufflés have risen and are golden brown on top. Avoid opening the oven door during baking to prevent them from collapsing.

Serve immediately to enjoy the soufflés at their peak puffiness.