Peel and grate the marrow on a clean grater and place in water simultaneously to keep it from discolouring.
Drain the water in strainer.
Leave for 5-10 minutes to drain properly.
Do not squeeze the grated marrow as it will discolour.
Put the marrow in a pan along with the water and milk. Cook on medium heat stirring to avoid sticking to the pan.
When marrow is cooked add the sugar and keep stirring until sugar dissolves and the moisture evaporates leaving the halva dry.
Taste for sweetness. If more sugar is required add it at this point and repeat above procedure.
Keep a handful of khoya aside and crumble the remaining on the halva. Cook on low heat stirring constantly for 5-10 minutes.
Remove from heat before the halva turns brown. Place in serving dish, sprinkle remaining khoya, pistachios and almonds and decorate with silver varq if desired.