Corned beef: add 2 of your 4 cups of water to a medium-sized pot. Add kosher salt, granulated sugar, cloves, allspice berries, pink curing salt, coriander seeds, mustard seeds, black peppercorns, and bay leaves to the water and bring to a boil. This is your brine. 

Allow the brine to cool slightly and add the last 2 cups of water. 

Add your 3 to 4-pound brisket to a container that you can store in the refrigerator for the next five days. Cover the brisket with your brine. Add more water if needed to keep the brisket fully submerged in the brine. 

Store the container with the brisket for the next five days. At least once a day, flip the brisket and stir up the brine. 

After five days remove the brisket and discard the brine. Rinse off the brisket in cold water until it is clean of all brine, seeds, and peppercorns. 

Preheat oven to 300 F (148 C).

Add the brisket to an oven-safe pot or dutch oven that will hold it. Add as much water as needed to fully cover the brisket.

Over medium-high heat, bring the pot containing the brisket and water to a boil. Once it has come to a boil, remove from the heat, cover the pot and add it to the preheated oven. If you do not have an oven-safe lid for this pot, you can wrap the top in two layers of aluminum foil. 

Cook for 3 to 4 hours until the corned beef is very tender when pierced with a knife.

Allow corned beef to cool for at least an hour before slicing. Slicing is best if the meat is cool, so resting overnight in the refrigerator would be best. Meat slices best when it is firmer and cooler.

Slice as thin as possible against the grain so that the resulting slices are very tender. 

Reuben Cuban sauce: in a small bowl combine all ingredients. 

Store in the refrigerator for less than 2 weeks or so.

Sandwich assembly: slice your Cuban roll.

Add Reuben Cuban sandwich sauce all along both sides of the roll. Lay your slices of Swiss cheese on the bottom roll.

Top the Swiss cheese with slices of corned beef. Add sauerkraut and pickles on top of the meat. 

Top the kraut and pickles with your other slices of Swiss cheese and top that with the top of the bread roll. 

Cook the sandwich in a panini press until the bread gets crusty and browned. If you do not have a panini press, you can use a hot cast iron skillet with another skillet on top of the sandwich, pressing it down. This will griddle one side and you will have to flip the sandwich but it will work.