Mix together the graham cracker crumbs, sugar, and butter. Press into a 9-inch tart pan. Bake in a preheated oven for 6 minutes. Remove and cool
In a large saucepan bring the cream and butter to a simmer. Remove from heat and add the chocolate chips. Cover and let stand for 5 minutes. Stir until smooth. Pour the chocolate into the cooled crust and refrigerate at least 2 to 4 hours. Can be made the day ahead.