1. Choose fully ripe but not overripe, or even slightly spoiled mangoes.
2. Peel and cut into large slices with a clean stainless steel knife.
3. Discard the stones.
4. Sprinkle some castor sugar at the base of a freezer container.
5. You may use freezer-proof plastic see-through containers for convenience.
6. Make sure the lids are airtight.
7. Pile about 2 inches of mango slices.
8. Sprinkle some more sugar.
9. Repeat till container is full or mangoes are exhausted.
10. Top with a final layer of castor sugar.
11. Pack down tightly with a flat spoon.

Close lid tightly and freeze.