Wash and peel the raw mangoes.
Add water to a pressure cooker. Place the raw mangoes in a container inside the pressure cooker.
Pressure cook for 2-3 whistles.
Once the mangoes have cool down, extract the pulp and discard the seeds.
Take this mango pulp in a mixing bowl. Add jaggery powder, black salt and spices (green cardamom powder, roasted cumin powder, black pepper powder) to it.
Mix everything very well. You may strain this concentrate as well. Transfer the concentrate in an air tight glass jar and refrigerate.
To make the aam panna, just dilute the concentrate with drinking water and serve.