1. Preheat oven to 350. 2. Warm the pastrami and sauerkraut in saute pans with some butter until hot and fragrant (use 2 separate pans). 3. Butter the outside of both slices of bread. Add Thousand Island to both sides and mustard to one side. 4. Pile the pastrami, swiss and sauerkraut onto the bread. 5. Toast in the oven until both sides are crispy and golden. You may need to flip in order to achieve this. Add pickles if desired or serve with pickles on the side.