Preheat oven to 170 degrees. Cover a brownie pan with aluminum foil or parchment paper – I had run out of parchment, so used aluminum foil. Brush butter to grease well.

In a bowl, start melting the butter on top of hot boiling water. As it starts to melt, add the chocolate and stir till completely melted and well combined.

Take off the heat, add the cocoa powder and mix till smooth.

Add in eggs, one after the other and stir after each addition.

Add in the sugar and vanilla essence and mix.

Finally add in the flour and walnuts and stir till you get a really thick batter. I used a whisk throughout this whole process.

Pour half the batter into the brownie pan. Drop spoonfuls of DDL, 1/4 cup, all over the batter.

Using a knife, swirl the DDL all over the batter. Pour the remaining batter on top and repeat the DDL pattern with the quantity left.

Bake for 45 minutes till firm to touch.

Allow to cool completely, pull along with the aluminum foil off the pan. Cut into slice and serve. Taste even more delicious the next day!