Prepare the Seasoned Tempeh: In a medium saucepan, combine the liquid aminos, onion, garlic, bay leaf, and 2 cups (480 ml) of water.
Add the sliced tempeh and bring the mixture to a simmer over medium heat.
Reduce the heat to medium-low and let it gently simmer for 20 minutes.
Remove from heat, cover, and allow the tempeh to cool completely in the flavorful broth.
Make the Thousand Island Dressing: While the tempeh simmers, whisk together the vegan mayonnaise, relish, and ketchup in a small bowl until well combined.
Set aside.
Build the Sandwiches: Toast 8 slices of rye bread and set them aside for the tops.
Drain the cooled tempeh, discarding the broth and aromatics.
Arrange the tempeh slices evenly on the 8 remaining, untoasted slices of bread.
Top with slices of vegan cheese.
Melt and Serve: Place the open-faced sandwiches on a baking sheet and toast or broil for 3 to 5 minutes, until the cheese is fully melted and bubbly.
Top each sandwich with ¼ cup of sauerkraut.
Spread the Thousand Island dressing on the toasted bread slices and place them on top to complete the sandwiches.
Slice diagonally and serve warm.
Squeeze the sauerkraut thoroughly in a clean kitchen towel or paper towels to remove excess moisture. This is the key to preventing a soggy sandwich.