Preheat the oven: Preheat your oven to 325°F (160°C). Prepare a water bath by placing 4 ramekins in a large baking dish, ensuring they're spaced evenly.

Heat the cream: In a medium saucepan, heat the heavy cream over medium heat until it begins to simmer (don't let it boil). Remove from heat and set aside to cool slightly.

Whisk the egg yolks: In a separate bowl, whisk the egg yolks and powdered erythritol until the mixture is pale and creamy. Slowly whisk in the Irish whiskey and vanilla extract.

Temper the eggs: Gradually pour the warm cream into the egg mixture, whisking continuously to prevent the eggs from curdling. Mix until smooth and fully combined.

Bake the custard: Divide the custard mixture evenly among the ramekins. Pour hot water into the baking dish, filling it halfway up the sides of the ramekins to create a water bath. Bake for 40-45 minutes, or until the custard is just set and slightly wobbly in the center.

Cool and chill: Remove the ramekins from the water bath and allow them to cool to room temperature. Refrigerate for at least 2 hours, or preferably overnight, to set completely.

Make the brûlée topping: Before serving, sprinkle 1/2 tablespoon of granulated erythritol evenly over the top of each custard. Using a kitchen torch, carefully caramelize the sweetener until it forms a crispy golden-brown crust. If you don't have a torch, you can place the ramekins under the broiler for a few minutes, watching closely to avoid burning.

Serve: Let the brûlée cool for a minute to allow the crust to harden, then serve and enjoy!