In a pan, combine milk and cocoa powder till lump-free. Add condensed milk and combine well.
Cook on medium flame and mix. Add butter and cook till butter melts. Stir continuously to avoid burning. Once the mixture comes to a boil, switch off the flame.
Add cashew nut powder, digestive biscuit powder and combine well.
Now, switch on the flame and cook the mixture for 2 mins on medium flame.
The Mixture thickens and separates from the pan after 2 to 3 mins. Switch off the flame.
Add walnuts, almonds, and combine. The Chocolate mixture is ready to set.
Transfer the mixture to a 5-inch square dish lined with baking paper. Level the mixture.
Melt dark chocolate and butter. Pour it on the mixture and level it. Decorate with melted white chocolate.
Refrigerate for 2 hrs or till set.
Cut in squares and enjoy!