Have ready a fine-mesh strainer suspended over a 2 cup glass measure with a spout.
In a food processor, process the chocolate until very fine. Transfer it to a small heatproof glass bowl.
In a 1 cup or larger microwavable measure with a spout (or in a small saucepan over medium heat, stirring often), scald the cream (heat it to the boiling point; small bubbles will form around the periphery) and pour it over the chocolate. Cover the bowl for 5 minutes to let the chocolate melt. Using a silicone spatula, gently stir together the chocolate and cream until smooth. Stir in the bourbon until smooth. Press the mixture through the strainer and cool it to warm room temperature so that it is still fluid but not warm to the touch (75° to 82°F/24° to 28°C). (This takes only about 10 minutes, so set it in a warm spot to keep it pourable. If it becomes too firm, reheat it in the microwave with 3 second bursts, or in the top of a double boiler.)