This recipe is based on one from Sarah Leah Chase's cookbook, COLD WEATHER COOKING. In the original recipe, Chef Sarah uses a Hazelnut crust, which will be included at the end of this recipe. I prefer a regular pie crust. Although not a baker, I make a foolproof crust with my food processor. However, even a ready-prepared purchased crust works fine, too. I won't tell if you won't. Pears can be poached and custard made a day ahead and refrigerated, just bring to room temp before baking.