Soak the adzuki beans overnight for at least 8 hours in a large bowl. At this point, you can add the kombu alga.
When you are ready to start cooking, drain the beans and wash them thoroughly. You can keep the kombu alga and add it to the pot.
Chop the onion, the garlic, the carrot, and the celery and place them in the pressure cooker with the oil.
Wash and chop also the cavolo nero but keep it separated from the other veggies.
Turn on the fire to medium heat and start browning all the veggies while keeping stirring.
Add the adzuki beans with the kombu and stir still a little bit.
Add water to cover everything. The water needs to be some 2 to 3 cm above the red beans and the veggies.
Now add the salt, the thyme, the rosemary, the bay leaf, and the chopped cavolo nero.
Make sure your ingredients don't go above the limit line of your pressure cooker, then close it, and from the first whistle cook for 45 to 50 minutes at medium heat.
Serve hot adding a sprinkle of black pepper and a drizzle of olive oil. When serving, you can also add a grain of your choice.