Cooking the filling and thickening it with cornstarch prevents this pie from having a soggy bottom. However, even with a cooked filling, a fruit pie will never have a crisp bottom, unless you blind bake it beforehand. To do this, line your unbaked pie crust with parchment paper and fill with pie weights (or dried beans), then bake at 375ºF for about 15 minutes or until the edges begin to brown. Then, remove the pie weights and parchment paper and continue baking for another 8 minutes, or until the crust is just beginning to gain color. Finally, brush the crust with egg wash and return to the oven for a minute, just to set the egg! It is then ready to cool slightly and be filled with the fruit filling!