In a blender, blend 200 grams of fresh blackberries to make a smooth puree. Keep it aside.
In a non-stick pan, heat 1 tablespoon of ghee on medium flame. Add 200 grams of grated khoya (mawa) and cook for 5-7 minutes, stirring continuously until it becomes soft and slightly golden.
Add 200 grams of sugar to the khoya and mix well. Cook for another 5 minutes, stirring continuously until the sugar dissolves completely.
Add the blackberry puree to the khoya mixture and mix well. Cook for 10-12 minutes, stirring continuously until the mixture thickens and starts leaving the sides of the pan.
Grease a square or rectangular tray with ghee and pour the barfi mixture into it. Spread it evenly and let it cool for 10-15 minutes.
Once the barfi has cooled down a bit, cut it into square or diamond-shaped pieces. Allow it to cool completely and set for at least 2 hours or until firm.
Gently remove the barfi pieces from the tray and serve. Store any leftovers in an airtight container.