You have the option to either bake or fry the tofu. If baking, preheat the oven to to 200C (390F) and line a baking tray with baking paper, and brush with a small amount of oil.
Cut your tofu into slices (roughly 0.5" thick) and lay them out over a large plate or board. Sprinkle the soy sauce over them and set aside to marinate while you make the other elements.
Add the cornflour to a shallow dish.
Make the buttermilk by whisking the ingredients in a shallow bowl and set aside.
Make the panko mix by combining everything together in a shallow dish.
Dip each piece of tofu in the cornflour and make sure it's coated, then dunk in the buttermilk, and then into the panko mix (you may need to press down slightly so it's all covered)