In a well-greased 8-inch pie pan, spread the dough evenly with your hands. Bake in preheated oven for 12-14 minutes, until slightly golden on the edges.
Make the custard filling. Without turning on the heat, whisk together all custard filling ingredients in a medium saucepan. After cornstarch is well-combined with the other ingredients, heat the filling on medium-low until thickened.
Make the cranberry layer. In a medium saucepan, stir together the cranberry layer ingredients, and heat on medium until the cranberries pop and become mushy.