Preheat your oven to 350 degrees Fahrenheit (175 degrees Celsius).
Place 4 slices of rye bread on a baking sheet. Layer each slice with pastrami, then a slice of Swiss cheese.
Bake in the preheated oven until the cheese melts and the pastrami is heated through, about 10 minutes.
Remove from the oven and top each sandwich with sauerkraut and a generous amount of Russian dressing.
Finish with the remaining slices of rye bread.
Slice each sandwich in half before serving. Enjoy your pastrami sandwich while it's warm.
Notes
Always toast the bread slightly. It provides a crunch and prevents the bread from getting soggy due to the dressing.
Thinly slice the pastrami for easy eating. It should be thick enough to provide flavor, but thin enough to bite through easily.
Layer the ingredients evenly. This ensures that you get a bit of everything in each bite.
Warm the pastrami and melt the cheese. This can be done in a skillet or in the oven. It enhances the flavors and provides a nice contrast to the cool sauerkraut and dressing.
Make sure to drain your sauerkraut well. This will prevent the excess liquid from making your sandwich soggy.