In a large bowl, combine cold water, sea salt, bay leaves, black pepper kernels, and lemon slices. Stir until all salt has dissolved. Submerge turkey breasts in the brine and refrigerate for 4-7 hours. If the meat is floating, place a plate on top and weigh it down.
When done, remove the turkey from the brine and pat dry with a paper towel. Let it come to room temperature.
Meanwhile, preheat the oven to 350F (175C) and prepare a roasting pan.
In a small mixing bowl, combine the melted butter, garlic, thyme, salt, and pepper to taste.
Brush the turkey with the butter mixture on each side (leave some butter for later) and bake for 20-25 mins or until slightly undercooked. Then, remove from the oven, brush the rest of the butter mixture on top, and broil for 5 minutes or until internal temperature reaches 165F (74C).
When done, remove from the oven, place a piece of foil on top of the baking dish, and let the turkey rest for 5-10 minutes, then slice and serve.