If you don't have an actual double boiler, you can easily create your own! Fill a medium saucepan a fourth of the way with water and bring the water to a gentle boil. Then reduce to a simmer on the lowest heat possible and set a small or medium heat-proof glass bowl mixing bowl on top of the saucepan. Make sure the bowl sits snugly in the saucepan so there is no space around the edges, and the bottom of the bowl doesn't touch the water in the saucepan. Add the chocolate to the bowl and continuously stir until it is melted. Remove the bowl from the heat and continue the recipe as outlined.