Preheat the oven to 180 degrees C (350 F) and line a baking tray with a sheet of parchment paper.
Add the tempeh to a saucepan and just about cover it in water, simmering for 5 minutes. Drain if there is any water left.
Prepare the sauce by stirring together the tamari, balsamic vinegar, coconut sugar, apple cider vinegar, peanut butter, smoked paprika, cumin, garlic powder, cornstarch and water. Pour the sauce into a small pan and stir over a medium heat for around 3 minutes, until it thickens.
Stir the tofu with around ½ the sauce and transfer to the baking tray. Bake in the preheated oven for 20 minutes, until crispy and golden brown.
Stir the baked tempeh with the rest of the sauce and serve.