Heat a pan and add peanuts to it. Dry roast the peanuts up to crunchy. Then take off from gas and allow it to cool down. Now remove the skin of the peanuts and allow it to cool down completely. Then make a coarse Powder. If you grind  peanuts in warm condition, it will be a lump not powder. 

In the same pan add sesame and dry it. Let the sesame seeds cool down. Then reserve 3 tbsp of roasted sesame aside and make a coarse Powder out of the rest.

In a non stick Kadai heat ghee, add jaggery and water to it. Let the jaggery melt and don't boil. Over cooked jaggery will give a hard Modak. Then add powdered peanuts, sesame and whole sesame and give a quick mix. Switch off the gas immediately.

Bring out the mixture to a plate and allow it to cool down. When the mixture come down to a touchable temperature stuff it in a greased Modak mould to shape Modak. Stuff properly without gap. Carefully demould it and keep on a plate. Similarly prepare all the modaks.