Separate the rose petals from the flowers and wash them well with enough water.
Now take the washed petals in a big bowl and add 3 cups of water in the bowl (the water should be enough to submerge the petals completely)
Now cover the bowl and let the petals soak for a day,keep mixing and gently pressing the petals 3-4 times in between.
Next day strain the flowers and keep the water and flowers separately.
In a pan add 850 gms of sugar and 2 cups of water and boil on medium heat till the sugar melts and the syrup become sticky like gulab jamun syrup/chashni.
Add 3-4 drops of lemon juice to clear the sugar syrup scum.
Now add the rose water( water in which you have soaked the roses and now strained) in the sugar syrup and just give it 2 boils.
Switch off the flame and add the cardamom powder and the rose petals.
Let the syrup come to room temperature and then cover the pan with a lid and let it rest overnight.
Next day filter the syrup to remove all the petals and store the syrup in a glass bottle or jar.
Keep it refrigerated for a long shelf life.
How to serve- fill 1/3 glass with rose syrup ,put some ice cubes and then add chilled water .
Stir well and serve !