Put Sugar and water in a flat pan and bring it to a boil. Make 2 1/2 thread consistency of sugar syrup by stirring on low heat for 5-7 minutes. Remove from heat.
Add grated Khoya to the hot syrup. Stir continuously for 3 – 4 minutes.
The mixture will start to thicken and turn into a soft paste. If still runny, return to fire and stir on very low heat for 2 minutes.
Divide the basic Burfi mixture in to two equal parts. Transfer one portion to a greased Burfi tray or loaf tin to get 1/2 ” thick burfi. Keep aside for 15 minutes in the freezer.
To the Khoya in the pan, add the cocoa powder and mix well to blend. More cocoa can be added as per your taste. Add the chocolate food color if you like a darker color. Keep aside.
When the plain burfi is set, heat the chocolate Khoya mixture in a pan, and stir for 1-2 minutes on very low heat till it becomes soft enough to spread. Remove from heat. Spread over the set plain Burfi and tap lightly to level.
Keep aside for 15-20 minutes in the freezer to set. Cut to pieces and put some silver leaf for decoration.