Peel a mango. Hold it upright with the broad end (where the fruit is attached to the stem) on top. Cut following the contour of the seed, you will get the pisngi (cheek). Cut this flesh into 1 cm thick slices lengthwise as you would thick fries. Do to the other cheek. Discard the seed. Immerse the finished cuts in the water. This will prevent discoloration. Repeat with the remaining mangoes.
When you are ready for the next step, remove the mango slices from the water. Wash and drain well using a colander.
Brining the mango slices
You will need plastic containers with lids.
Spread a layer of mango slices and sprinkle with rock salt. Add another layer of mango and sprinkle again with rock salt. Repeat the process until all the slices are salted. This method ensures even salting of the mangoes. Do not stir or toss as this will dislodge the salt between the layers.
Cover your container with a lid. Do not add water!
After 12 hours, the salt would have started pulling the moisture from the mangoes and you will notice there is now liquid in the container. Do not discard this liquid but turn the mangoes over so the brine can also soak the top layer. Cover the container again with a lid.
After another 12 hours, turn the mangoes again and check if the mangoes are pliable by taking a piece of mango and try to bend it in half. If it breaks, the mangoes will need to soak longer.
Check again after several hours. If it doesn’t break when you do the test, you can proceed to the next step.
Drain mangoes well. Do not rinse in water.
Make the syrup
Prepare a large stainless pot with lid. It should be big enough to fit the mango slices. Use this pot to make the syrup.
Combine 1 kilo of sugar and a cup of hot water in the pot. Cook over medium heat. Bring to a boil and continue cooking until all the sugar is dissolved and the syrup lightly coats back of spoon.
Remove from heat and set aside to cool completely.
Adding syrup to the mango
Once the syrup has cooled, it may form a hard surface. When this happens, just place the mangoes on top and let it stand for several hours. This will dissolve the hardened sugar. Once it does, be sure to stir the mangoes and syrup to ensure even coating of the mango slices. Cover with lid and set aside for a day.
The next day, taste the mangoes. If the slices are too salty, you need to drain and discard the syrup. Make another batch of syrup. Again wait for the syrup to cool completely before putting in the mango. Stir to completely coat all slices. Cover again with lid and let stand for a day.
Repeat this process until the mangoes are just right to the taste – not too salty, not too sweat, but with still a hint of sourness. It usually takes two to three times of replacing the syrup before you can get it right.
Transfer the mangoes into sterilized jars with lid (preferably plastic ones as metal lids can rust from the salt). Make sure to immerse the pickled mangoes in its syrup to prevent dry out. Refrigerate.