Smoked Portobello and Gruyere Reuben

Name: Smoked Portobello and Gruyere Reuben
Ingredients: Smoked Portobello and Gruyere Reuben; 5 large portobello mushrooms, sliced lengthways into 1cm strips; 1/2 cup purple cabbage sauerkraut; 6 slices swiss gruyere; 8 slices rye bread; 2 tablespoons balsamic vinegar; 1 tablespoon extra virgin olive oil; cracked pepper; smoked sea salt flakes; Safflower Oil Mayonnaise; 1 tablespoon apple cider vinegar; 1/2 teaspoon yellow mustard; 1/4 teaspoon sea salt flakes; 1 pasteurised egg yolk; 1 tablespoon water; 1/2 cup safflower oil (or a LIGHT olive oil, depending on taste preference)