Peel and roughly chop the mangoes.
Add it in the blender along with half of the ginger.
Blend it until smooth.
Finely chop the garlic and remaining ginger.
Now in a pot or a pan, add oil.
Once hot, add in the chopped garlic and ginger.
Saute it on slow to medium for a minute until translucent or the raw smell of ginger goes.
Now add the pureed mangoes, chilli flaxes and mix. Cook for a minute.
Now add in the Sweetener, vinegar, salt and half of the water.
Cook it further for 2-3 minutes.
Now mix in the cornstarch with the remaining water and add it in the above mix.
Cook it further for 2-3 minutes until you get the desired consistency.
You can add more cornstarch to make it thick, for me 1 tsp was just perfect.
Let it cool completely.
Transfer it into an air tight container and store in refrigerator. Use as required.