Line 2 baking sheets with parchment paper.
Combine the milk chocolate and one dark chocolate pieces into a large bowl.
Add whipping cream and sugar to a saucepan bringing it to a boil.
Once it reaches a boil quickly remove the saucepan from the heat and add the instant coffee.
Whisk the coffee to combine it with the whipping cream and sugar.
When dissolved pour over the bar of chopped milk chocolate and chopped dark chocolate. Stir using a whisk until chocolate is melted.
Add whiskey. Stir to combine.
Cover this (ganache) with plastic wrap.
Set aside to firm up for at least 3-4 hours or overnight.
This needs to be firm enough to be made into a ball and hold its shape.
Using a large spoon to scoop ganache out and use your hands to roll into round balls.
Bring the water in the bottom half of the double boiler to a boil.
Reduce to a low simmer.
Add 2/3's of the chopped dark chocolate in the top half of the double boiler.
Stir constantly until the chocolate is almost melted.
Set 1/3 of remaining chocolate aside.
Remove from heat and allow to slightly cool.
Add the rest of the chocolate.
Stir until most of chocolate has melted.
Place some chocolate on the palm of your hand and roll a round ganache ball into it.
Place the chocolate covered truffles on the prepped cookie sheets.
Repeat until all of the balls have been made.
(If chocolate becomes too firmed and or cold place it in the microwave oven for 4-5 seconds.)
Dip truffles once more into chocolate.
Allow to slightly harden before drizzling more chocolate onto the truffles