Heat the cream until it just comes to a simmer. You can do this in a small saucepan on the stove, or in a bowl in the microwave.

Meanwhile, if you are using bar chocolate, chop it into small pieces.

Add the chocolate and chili powder directly to the hot cream. Let it sit for about 5 minutes, and then stir until the mixture is smooth and glossy. If the chocolate isn't completely melted you can heat it for about 15 seconds in the microwave and stir again.

Cover with plastic wrap and set the bowl in the refrigerator to cool for about 2 hours, or until the ganache has hardened enough to be scoopable.

Using a small 1" sized scoop, a melon baller, or a teaspoon, scoop up small amounts of chocolate and set them on a plate. Work with about 10 truffles at a time.

Roll each truffle around in your palms until it is a smooth ball.

Roll each truffle in the cocoa powder until they are completely coated.

Repeat the process with the rest of the truffles, cleaning your hands in between batches.

You can store the truffles in the refrigerator, and you can serve them chilled or at room temperature.