In a wide container, mix together soy sauce, vinegar, maple syrup, BBQ seasoning and sauce. Marinate the tempeh steaks in the mixture for at least an hour (the longer the better).
1/3 cup of soy sauce, 1/4 cup of apple cider vinegar, 1/2 tablespoon of maple syrup, 1.5 tablespoons of BBQ seasoning, 2 tablespoons of BBQ sauce, 300 g of tempeh