Preheat the oven at 220° Celsius.
Cut the tofu into small cubes. Mix together all the ingredients for the marinade and pour over tofu. Put in an airtight container and let rest for 1 hour, preferably over night in the fridge. Make sure to turn the container from time to time.
Peel and thinly slice sweet potato. Line up sweet potato slices on a baking sheet, sprinkle on some salt and bake in the oven for 15 minutes.
In the meantime start cooking quinoa according to the instructions on the packaging. I poured mine in a pan together with the water and bouillon cube, started heating and cooked the quinoa until all the water evaporated. Keep warm.
Remove baking sheet from the oven, baste the sweet potato slices with olive oil and bake for another 15 minutes in the oven.
Heat a frying pan and add the tofu cubes (without marinade), sear them for only few minutes until they turn brown and crispy.
Serve in a bowl and decorate with nori leaves.