Place chopped chocolate in a wide, heatproof bowl (I place mine in my stand-mixer bowl. This way I can melt the chocolate and then whip it, using only one bowl)
In a heavy pan, bring the cream and salt to a boil. Turn down the heat and let the cream simmer for a full minute. Stir often, making sure the cream does not burn.
Immediately take the cream from the heat and pour evenly over the chopped chocolate. Resist the temptation to stir. Allow to sit for 2-4 minutes in order to melt the chocolate.
When the chocolate has melted, stir the ingredients together with a heatproof rubber spatula or stand mixer. Use the spatula to stir any larger pieces of chocolate in to the warm cream to dissolve.
You should end up with a smooth, glossy mixture referred to as ganache. Add the balsamic to the ganache and mix thoroughly. The ganache will thicken as it cools and when it reached room temperature, can be piped. To make traditional truffles, pipe small portions ( approximately 2 tsp.) of ganache on to parchment paper or another non-stick surface. These portions will continue to cool and solidify and can then be rolled in to small balls. Dredge the balls in cocoa powder.
If used while warm, the ganache can be poured over cakes or used as a fruit dip.