Prepare the filling: In a small bowl, mix the drained sauerkraut with the caraway seeds if using. Season with a pinch of black pepper. Set aside. You should see the sauerkraut looking dry and slightly fluffy, not wet or clumped together.

Butter the bread: Lay out your eight slices of rye bread and spread the softened butter evenly on one side of each slice. The butter should be soft enough to spread without tearing the bread — you'll hear a gentle squelch as you spread it.

Assemble the sandwiches: Place four slices of bread, buttered side down, on a clean work surface. Spread about a tablespoon of Russian dressing onto each slice. Layer on the sliced beef, folding it to fit neatly, then add the drained sauerkraut, and finally top with Swiss cheese slices. Place the remaining four bread slices on top, buttered side up. Press down gently — you want the sandwich to feel compact but not squashed.

Heat the pan: Place a large frying pan or skillet over medium heat and add the vegetable oil. Swirl the pan until the oil shimmers and you can see tiny ripples on the surface — this usually takes about 30 seconds.

Cook the sandwiches: Carefully place two sandwiches in the pan (don't overcrowd). Cook for 3–4 minutes on the first side. You'll know it's ready when the bottom is a deep golden brown and you can hear a gentle sizzle. The smell of toasting rye and melting cheese will fill your kitchen.

Flip and finish: Using a spatula, carefully flip each sandwich. Cook for another 3–4 minutes, pressing down gently with the spatula once or twice. The second side should be equally golden, and the cheese should be fully melted — you'll see it oozing slightly at the edges when you lift a corner to check.

Rest and slice: Transfer the cooked sandwiches to a cutting board and let them rest for 1 minute. This allows the cheese to set slightly, making slicing cleaner. Cut each sandwich diagonally with a sharp knife — you'll hear a satisfying crunch as the crust gives way.