In a ziplock bag combine ½ cup soy sauce, ⅓ cup mirin, 2 tsp rice vinegar, ¼ cup sugar, 1 tsp garlic powder, and ½ tsp ginger powder. Let it marinate for 30 minutes. Place a grill pan over medium-high heat. Cook the eggplant until each side has crisped up, about 4-6 minutes per side. Set aside.
In a bowl combine ½ cup soy sauce, 1 tbsp sugar, salt, and pepper. Toss the shrimp in and marinate for 30 minutes. Heat a pan over medium-high heat with 1 tbsp butter. Cook the shrimp until it turns pink, 2-3 minutes. Set aside.
It is time to work on building the four different sandwich layers. To make the bottom layer use 2 slices of multigrain bread. Add avocado, the eggplant and roasted red pepper. Top with balsamic vinegar and lettuce.
For the second sandwich, grab 2 slices of white bread. Add Japanese mayo, lettuce, ham, and prosciutto. Add another piece of lettuce and the cheddar cheese.
The third sandwich uses 2 slices of multigrain bread. Add Japanese mayo and the turkey. Top with lettuce, salami, and sprouts.
For the last sandwich grab the last 2 slices of white bread. Add Japanese mayo, tomato, and avocado. Top with shrimp and avocado.
Setting up the sandwich can be a bit tricky. I would recommend using bamboo sticks to have each of the sandwiches piled on one another.
