Melt the dark and white chocolate separately in two different bowls, either by microwaving or on a gas top in a double boiler.
If you are melting the chocolate in a microwave, keep stirring after every 15-20 seconds until it forms into a smooth sauce, to make sure that it is heated up uniformly and not getting burnt.
If melting on a gas top, place the grated chocolate in a small vessel. Boil water in a bigger vessel, simmer the flame, place the bowl containing chocolate in the water bath. The chocolate bowl should just fit into the water bath.
Once both the chocolates are melted, add ¼ cup condensed milk, icing sugar, cardamom-cinnamon powder, make a uniform paste.
Lastly add dessicated coconut, knead with hands to mix all the ingredients well. The final dough should be firm and tight, if required add few spoons of coconut powder to bring it to desired consistency.
Once both the doughs are ready, refrigerate for 30 minutes or so.
To get checker board pattern, you will need: Baking paper/ parchment paper/ any non sticking surface and icing sugar to sprinkle on work top, if the dough sticks.
Take the dough out of the fridge, place it on parchment paper. You can use any non sticky surface for this step or sprinkle some icing sugar on to the work surface .
Shape the ball of dough roughly into a rectangle with hands, close the paper from both the sides, enveloping the dough and start flattening the dough evenly with a rolling pin, until about 1-2 cm thickness.
Open the paper flaps, chop the sides to make it a even square / rectangle. The excess dough chopped can be used to make these small truffles/ balls rolled in dry coconut.
My final rectangle after chopping the uneven sides was 15 cm length x 10 cm width.
Mark indentations at every 1cm , and cut into thin stripes.
Do the same with white chocolate dough.If the dough becomes too soft, refrigerate for 15-20 minutes and then proceed.
Now, build the log , from which the barfi pieces will be cut.In the first layer, place alternate stripes of dark and white chocolate. I placed five strips side by side of dark-white-dark-white-dark chocolate stripes.
In the second layer, constructed exactly above the base layer, but with alternate colours, i.e, if the base stripe is white, then the stripe above it will be dark. Keep building till 4-5 layers, so that there is alternate colours from top.
Once the dough is nicely chilled, cut 1-2 cm thick slices from the log to get a beautiful checkerboard pattern.