In a large pot, combine 1 gallon of water, 1 cup of kosher salt, and 1/2 cup of brown sugar.
Heat the mixture on medium heat, stirring until the salt and sugar are fully dissolved.
Once dissolved, remove from heat and add black peppercorns, dried thyme, dried rosemary, crushed garlic cloves, and bay leaves to the pot.
Allow the brine to cool to room temperature. If you're short on time, you can add ice to speed up the cooling process.
Once cooled, place your turkey in a large container or a resealable bag, and pour the brine over it, ensuring the turkey is completely submerged.
Seal the bag or cover the container and refrigerate for at least 12 hours (preferably 24 hours) before cooking.
After the brining time is complete, remove the turkey, rinse it under cold water, and pat it dry with paper towels before cooking as desired.