Note: On Primal Grill, Steven demonstrated Turkey Pastrami Sandwiches with kraut, pickles, and Russian dressing. And you could certainly stop there. But if you want to make a Reuben, the recipe is below.
Step 1 : Make the dressing. In a nonreactive mixing bowl, combine the mayonnaise, chili sauce, pickle relish, and black pepper. Refrigerate if not using immediately.
Step 2: Using a knife or pastry brush, spread or brush the slices of bread on one side with the butter. Place 2 slices of bread on a work surface buttered side down, then spread the top of each with 1 tablespoon of the dressing. Arrange the slices of pastrami on the bread, followed by the slices of cheese, trimming both so that they come just to the edges of the bread. Place the trimmings in the center of the sandwiches. Spoon 1/3 cup of the sauerkraut over each sandwich, spreading it out to the edges of the bread. Top each sandwich with half the pickle slices, if desired. Spread the unbuttered side of the remaining 2 slices of bread with the remaining 2 tablespoons of dressing, dividing it evenly between them, then place them on top of the sandwiches, dressing side down.
Step 3: When ready to cook, preheat your contact grill. Lightly coat the grill surface with cooking spray. Using a spatula, transfer the sandwiches to the grill and gently close the lid. Grill the sandwiches until the bread is browned and crisp and the cheese is melted, about 5 minutes. Cut each sandwich in half and serve at once.