Heat the oven to 375 degrees F.

Prick the sweet potatoes with a fork and bake them until they are soft, about 1 hour. Remove from the oven and set aside until they are cool enough to handle.

While the potatoes are cooking make the pastry: combine the flour, sugar, and salt in a large mixing bowl. Add the butter and mix with a pastry blender or your hands until the mixture resembles coarse crumbs. Pour in the ice water and work it in to bind the dough until it holds together without being too wet or sticky. Squeeze a small amount together, if it is crumbly, add more ice water, 1 teaspoon at a time. Form the dough into a ball, wrap it in plastic wrap, and refrigerate it for at least 30 minutes.

Sprinkle the counter and a rolling pin lightly with flour. Roll the dough out into a 10-inch circle. Carefully roll the dough up onto the pin and lay it inside a 9-inch pie pan. Press the dough firmly into the bottom and sides so it fits tightly. Trim the excess dough around the rim and pinch the edges to form a border. Place a piece of parchment paper over the crust and fill with uncooked beans or pie weights. Bake the pie crust until it sets, about 20 minutes. Remove the parchment and beans. Brush the bottom with the beaten egg white and set aside.

While the crust is cooking make the filling: When cool enough to handle, peel the sweet potatoes and puree the pulp in a food processor with 1/2 stick butter and a pinch of salt. Measure 1 1/2 cups puree into a bowl. In another bowl beat the eggs and sugar until the sugar has melted. Add the eggs to the sweet potato puree and whisk well. Add the cream, orange zest, cinnamon, and nutmeg and stir well to combine. Pour the mixture into the pie shell. Place the pie pan on a sturdy cookie sheet to catch any spills. Lower the oven temperature to 325 degrees F and bake until the pie is set but still jiggles slightly, about 40 minutes. Remove from the oven and allow it to cool.

Meanwhile, put the pecans on a baking sheet and bake them with the pie for about 10 minutes to toast them. Remove them from the oven and let them cool. Thaw the cranberries in a strainer set over a bowl to catch the liquid. Put the cookies, pecans, and cranberries into a food processor and pulse them a few times until they are coarsely chopped. Sprinkle the topping evenly over the cooled pie and serve immediately.