Melt the chocolate in double boiler & allow to it to cool.
Pre-heat the oven to 180 C.
Line 8″ baking tin with greased butter paper.
Sieve flour, baking powder & baking soda together.
In a separate bowl, whip together butter & condensed milk. Mix in vanilla essence & whip lightly.
Add flour & coke to the condensed milk batter alternatively. Start & end with flour.
Slightly warm walnuts for about 30 secs & coat it with flour so that walnuts do not sink to bottom. Warming will help in releasing the oil of dry fruits.
Now add melted & cooled chocolate to the batter.
Mix together for 2-3 minutes.
Add walnuts & just very lightly mix in.
Pour in the prepared tin & lightly tap it against the work surface. Bake for 15 mins or till done.