Roast the seeds on a griddle till they start to splutter and take on just a suggestion of colour. Remove from the pan and set aside to cool.
Place a heavy-based pan on the stove. Put in the ghee and the khoya and saute till it appears to be of a uniform consistency and looks slightly fried. Take off the heat; add the roasted sesame seeds and leave to cool.
In another pan, warm the sugar and water together over low heat, stirring a few times till the sugar dissolves. Make sure not to let it boil before the sugar dissolves. Once the sugar dissolves, let the syrup boil over high heat till it thickens.
Mix immediately into the cooled khoya mixture, stirring vigorously to blend well. As you mix it in, it will begin to set, so it is essential to blend it in as fast as you can.
Transfer on to the greased plate, pat to level, and leave to cool and set. Cut into pieces of desired size, using a sharp knife. Arrange in a serving dish and serve. Can be stored in an airtight container for 8-10 days or more.