Place cocoa and butter in grinder and mix until they form a paste.
Now, Fill the pan about 1/4 full with water and then place the bowl on top of the water.
Now, put the chocolate paste in the bowl and then heat until the mixture is as hot as needed.
Put the mixture back in the grinder and mix till smooth.
Then warm the milk to room temperature.
Add sugar, flour and milk to the paste and mix the batter well so that no lumps are formed.
Now pour the mixture into molds and place it in the fridge till they become hard. Take the pieces out and munch away.