Step 1

• Preheat your oven to 375°F (190°C).
• Generously butter four 8-ounce ramekins and dust the insides with flour, tapping out any excess.
• Place the prepared ramekins on a baking sheet.

Step 2

• In a medium saucepan, melt 2 tablespoons of butter over medium heat.
• Stir in the flour and cook, stirring constantly, for about 2 minutes until the mixture is bubbling but not browned.
• Gradually whisk in the warmed milk and continue to cook, whisking constantly, until the mixture thickens and comes to a boil.
• Remove from heat and season with salt, pepper, and nutmeg.

Step 3

• Stir in the grated Gruyere cheese and thyme until the cheese is melted and the mixture is smooth.
• Let the mixture cool for a few minutes, then beat in the egg yolks one at a time until fully incorporated.

Step 4

• In a clean, dry bowl, beat the egg whites with the cream of tartar using an electric mixer until stiff peaks form.
• Gently fold one-third of the beaten egg whites into the cheese mixture to lighten it, then carefully fold in the remaining egg whites until just combined.
• Be careful not to deflate the mixture.

Step 5

• Spoon the soufflé mixture into the prepared ramekins, filling each about three-quarters full.
• Run your thumb around the inside edge of each ramekin to help the soufflés rise evenly.
• Bake in the preheated oven for 20-25 minutes, or until the soufflés are puffed and golden brown.
• Serve immediately.