Preheat the oven to 370º C Gas Mark 5.
Cut the tempeh into ¼ inch thick pieces and set aside.
Combine the sesame oil, shoyu, hot sauce, (if using) garlic cloves, ginger and juice from one lemon in a small bowl. Whisk and transfer to a large, zip-closed plastic bag. Place the sliced tempeh in the bag and gently massage it with your hands to coat all the pieces. Refrigerate for 30 minutes.
Remove the tempeh from the marinade. Bake for 10 minutes, turn over and bake ten minutes on the other side until crisp and golden.
Serve.