Rinse the raw mangoes in water a couple of times. Place the mangoes in a 2-litre pressure cooker. Add 2 cups water.
Pressure cook for 2 whistles on medium flame or for about 8 to 10 minutes.
When pressure settles down on its own, then remove the lid. The mangoes would have become soft. The peels would have also separated if the mangoes are cooked well.

Gently pour the contents of the cooker in a fine strainer. Place a bowl underneath. Do not discard the water. Use this water to make aam panna drink.
Let the mangoes cool at room temperature. Place them in a bowl. After cooking the raw mangoes, the peel comes off easily.

With a sharp-edged spoon or a knife scrape and remove the cooked mango pulp directly in the bowl. Scrape from the peels also.

Collect the cooked mango pulp in a bowl. Discard the peels.
As a rule always add double the amount of jaggery or sugar to the mango pulp. The ratio is 1:2 for mango pulp and jaggery respectively. So before adding sugar or jaggery measure the amount of mango pulp in a measuring cup.
If you get 1 cup of mango pulp, then add 2 cups of sugar. I got about ¾ cup of mango pulp and so added 1.5 cups sugar.

Now add the required amount of sugar
Add cardamom powder, roasted cumin powder, black salt, crushed black pepper or pepper powder. Mix very well. You could also use a blender or hand churner to blend the aam panna syrup.

Pour the aam panna syrup in a clean glass bottle or jar. Store the bottle or jar in the fridge.

Serve aam panna immediately.