Transfer it to fire and start cooking it in low flame by stirring continuously.
When plum became mussy and releases all their juice, switch off the flame.
Cool it and blend it into a smooth semi thick liquid consistency.
Pass the liquid through a sieve to strain it.
Again heat up the liquid and cook till it reduces to half and becomes a thick concentrate. Cool it down.
Add black salt and give a nice mix.
In a serving glass add tbsp of jamun concentrate and with the help of the back of the spoon slowly add the 7up followed by sparkling water.
(fill half of the glass with 7up then add sparkling water). Its ready to serve.