Put the egg yolks into a big bowl or container. Include the appropriate amount of sugar (depending on the size of the baking dishes), vanilla extract, a little bit of salt, and bourbon (if desired), then mix them all together until a light-colored consistency is achieved.

Combine the cream with the whisk and mix together. Stir until all the sugar has completely dissolved.

You have the choice to put the custard mixture in a saucepan and gently warm it over medium heat, continuously whisking until it becomes warm and starts to release steam. The sugar should also completely dissolve. Please refer to the recipe notes for more information.

The custard mixture might have bubbles on top. Cover it and let it sit, so the bubbles can go away. You can also stir gently to get rid of some of the bubbles.

Divide the custard into six half-pint jars and seal them with the lids. Afterward, slightly loosen the lids to prevent excessive pressure and ensure the jars are not tightly closed (for more information, please refer to the provided post for instructions).

Pour hot tap water into your sous vide container. Connect your sous vide circulator and adjust the temperature to 179°F - 181°F / 82°C - 83°C. Begin the sous vide process.

Carefully place the jars into the water, which will enable them to reach the desired temperature together with the water.

Once the circulator has reached the desired temperature, begin counting the cooking time for one hour.

After one hour, take out the jars from the water container and fasten the lids by using a cloth napkin to provide a better grip since the jar and lid will be extremely hot at this point.

Allow the custards to cool entirely until they reach the temperature of the room.

Move the jars to the refrigerator and allow them to cool down for the duration of the night.

When you are prepared to serve them, you may need to carefully use a spoon to remove the lids from the jars in order to break the seal.