Butter a tray and keep it ready.
In a heavy bottomed pan mix sugar and water.
Bring it to boil on medium flame. Keep stirring to avoid burning the syrup.
When it boils rigorously, add the condensed milk to the syrup and keep on stirring.
Add the vanilla essence and let it boil until it becomes thicker. Keep on stirring to avoid burning the mixture.
Once the mixture starts thickening, add in the cashew and mix well.
Now keep a bowl with cold water nearby to check the consistency.
When the mixture starts leaving the sides, you need to check for the consistency.
Drop a little bit of the mixture into the water. It should form a ball which is not too soft and not too hard.
When the mixture reaches that consistency, pour it immediately into the buttered tray and with a spoon, smooth the top.
When it cools down, cut into squares.
Allow it to cool completely before storing it in a jar.
