Here is a super quick recipe for a delicious sandwich.
Rye Bread (Pictured is Russian Rye, but any will work)
Heat Sauerkraut in a pan to warm and dry the liquid so that your sandwich is not soggy. Next, assemble the sandwiches. Take two slices of bread, two slices of swiss cheese and two to three slices of pastrami, depending on the thickness. Spread mayonase on one slice of bread and mustard on the other, then cover one slice with a piece of cheese followed by pastrami, sauerkraut, another slice of cheese and the topped with the final slice of bread. Butter the outside of the sandwich and heat in a pan until bread is toasted and cheese is melted.