A good Reuben sandwich needs an even layer of butter all over the bread to get the right crust, which may be tough when using cold butter that doesn't spread well.
To make this step a breeze, take the butter out of the fridge for at least half an hour before using it so it softens enough to spread more easily on the bread.
However, too much moisture can lead to soggy bread. Since sauerkraut usually comes in a jar full of brine, strain it in a sieve to drain off the excess and use crisp sauerkraut.
Since a Reuben has many components, including melted cheese, sauerkraut, and dressing, which may lead to soggy bread, it's best to toast the bread on both sides.
You can toast your bread slices, add the sandwich fillings, and press your Reuben, or try grilling each slice on both sides in your pan before adding the fillings and closing it.
Mince your onion finely and mix it with mayonnaise, ketchup, horseradish, Worcestershire sauce, paprika, and salt for a tangy, sumptuous Russian dressing.
Garlic butter can truly amp up a Rueben. It adds complexity to the rich dish and complements the horseradish in the dressing and the saltiness of the corned beef.