Pour half of the heated cream over the chocolate pieces and let it rest for about 1 minute. The chocolate will be starting to melt. Use a whisk and start to incorporate the melted chocolate into the cream. Slowly begin to add the remaining cream and whisk until the chocolate mixture is smooth and glossy.
Add the butter and use a spatula to stir until the butter is melted. The mixture should be dark and glossy. Set aside at room temperature while you bake the crust.