To make the chocolate ganache, I used a ratio of two parts semi-sweet chocolate to one part heavy cream. (Weighing the ingredients will give you the most accurate ratio.) Place 8 ounces. (227g) of chopped semi-sweet chocolate into a medium bowl. Heat 1/2 cup (4 oz/ 118ml) of heavy cream in a small saucepan over medium heat. Bring the cream just to a boil. Pour the hot cream over the chocolate, making sure to cover it completely. Let sit for 2 minutes, then stir gently until smooth.