Melt chocolate in a double boiler or the microwave. Double Boiler: Place a glass or metal bowl over a saucepan of boiling water. Turn the heat to lowest setting and add chocolate that is chopped or in chips. Stir chocolate until fully melted. Microwave: Place chocolate in a bowl. Heat in increments of 30 seconds, stirring after each time, until the chocolate is melted.
Add cream and butter to saucepan and place over medium-low heat. This will not take long; do not let the cream boil. Swirl until butter is fully melted. Take away from heat and add cayenne. Stir to make sure mix until it is fully incorporated.
Get your bowl of melted chocolate and add the cream, butter, and cayenne mixture a 1/4 cup at a time. Fully incorporate the liquid before you add more. This take longer but ensures a nice emulsion and smoother ganache. You can use an immersion blender once you added more than half the liquid.
Cover in plastic wrap place it in the refrigerator for a few hours. Once cooled, it can be piped ganache onto cakes or melt and drizzle over anything edible!