Peel and slice the raw mango into medium thickness julienne.
In a kadhai, add the mustard oil, lower the flame when it starts to smoke.
Add the broken chilli and fry till it almost burns and the oil is infused. Then take out of the kadhai and keep aside.
Add the mustard seeds and fry. Next, add the mango slices and fry it well.
Add a small pinch of salt, a small pinch of turmeric and a pinch of sugar. Add a splash of water, cover and cook the mango till it softens.
Once it softens, add the sugar till it's sweet enough and cook till the sugar melts. Add enough water to make a light broth. Keep tasting the broth for your preferred sweetness.
Let it boil for 2 minutes covered, then add the fried chillies and boil it for 1 minute uncovered.
Turn off the flame and let it cool. You can eat it warm, hot or chilled with ice cubes as desired.