Mix first three ingredients and pat into a 10-inch springform pan.
Cream the cheese until light. Add sugar and beat some more. Add eggs one at a time and beat after each. Mix in cream, vanilla and cornstarch. Stir in the candy, saving 1/2 cup for topping.
Pour into crust and bake at 350 degrees for 1 hour or until outside edge is firm and middle is still soft. (Keep a pan of water in the bottom of oven as the cake is baking to keep the humidity high and keep the cake from cracking.)
When the cake comes out of the oven, run a knife around the edge. Cool for several hours, then top with more chopped Reese's and drizzle with melted chocolate.
Please note that some ingredients and brands may not be available in every store.