Preheat your oven to 375°F and butter six 6-ounce ramekins. Dust with granulated sugar and set aside.

Heat the milk in a saucepan over medium heat. Split the vanilla bean in half and scrape the seeds into the milk. Bring the milk to a simmer and remove from heat.

In a separate saucepan, melt the butter over medium heat. Add the flour and salt and whisk to combine. Cook for 1 minute, stirring constantly.

Slowly pour the hot milk into the flour mixture, whisking constantly to prevent lumps. Cook the mixture for 2 minutes, stirring constantly.

Remove the pan from heat and add the egg yolks one at a time, whisking until fully combined.

In a separate bowl, beat the egg whites until they form soft peaks. Gradually add the sugar, continuing to beat until stiff peaks form.

Gently fold the egg whites into the flour mixture in three additions, being careful not to overmix.

Divide the batter evenly among the prepared ramekins, filling them about three-quarters full.

Use a straight-edged knife to level the batter in each ramekin, running the knife around the edge to create a small trench.

Place the ramekins on a baking sheet and bake for 18-20 minutes, until the souffles have risen and turned golden brown on top.

Remove the souffles from the oven and serve immediately.