Simmer milk in heavy bottomed kadai. Keep on stirring the milk and cook till it thickens and quantity is reduced to half. Once quantity is reduced, add mashed khoya barfi . Cook for 5 min.
Mix kesar in hot milk and add into mixture. Add sugar as per taste and cook for 5-10 min. Allow the mixture to cool down completely. Blend it using blender and churn to form a thick ice cream.
Keep the mixture in freezer till semi solid. Churn the mixture again. Repeat this procedure 2-3 times to avoid forming ice in the kulfi. Set the kulfi mixture in kulfi mould. Add few rose petals in the moulds.
Keep it in freezer for 7-8 hours till Kulfi is completely set. For serving, de-mould the kulfi and garnish with sliced or chopped nuts.