The judge at the Shelburne Museum asked the secret of Helene's piecrust. She told him it was the Crisco. Crisco shortening contains hydrogenated vegetable oils, which we normally discourage (but it does make for flaky piecrusts). Feel free to use an equal amount of unsalted butter as a substitute. This recipe makes two crusts, but you'll need only one for Helene's pie. (Label and freeze the second dough ball.)
In a food processor, pulse together Crisco, flour, and salt. Add icewater and pulse just until dough gathers from the sides of the bowl and forms a ball. You may need to add a bit more water; don't overprocess. Gather dough into two balls. Wrap them individually in plastic and refrigerate 1 hour or overnight. (You may freeze them up to six weeks; defrost in refrigerator before using.)
Heat oven to 350°. Dust a work surface with flour. Roll one dough ball out to an even round about 13 inches in diameter (for a 9-inch pie pan), one-eighth inch thick. Fold dough in half and lay it on top of a rolling pin. Lift gently and position it over pie pan. Unfold and ease dough into the pan without stretching it; cover the rim evenly.
Press dough gently against the sides and bottom. Trim the overhang to 1 inch. Tuck the dough overhang under itself and flute the edges. Lay parchment or foil into the pan, and place a layer of pie weights or dry beans on top. Bake 20 minutes; then take it out and let piecrust cool. Remove weights/beans.
Into a double boiler over simmering water, break chocolate into 2-inch pieces. Stir just until chocolate melts; don't let it boil. Spoon about 3 tablespoons melted chocolate onto bottom of piecrust, to keep it from getting soggy. Reserve the rest of the chocolate.
Sort 1 pint raspberries, picking out the finest, firmest, largest ones. Place a 3-inch biscuit cutter into the center of the pie crust. Arrange raspberries, tips up, around the outer circle. Place remaining raspberries into small saucepan over medium heat. Add 5 tablespoons sugar and 1 tablespoon tap water. Add more sugar to taste if you like. Mash berries; stir and mash occasionally until thickened, about 10 minutes. Strain to remove seeds. Whisk 1 teaspoon tap water with 1 tablespoon cornstarch and whisk into raspberry sauce. Let cool slightly, then pour over arranged raspberries in piecrust.
Sort blueberries. Fill center ring with the best and biggest. Refrigerate the pie. Place 1 pint remaining blueberries over medium heat. Add 5 tablespoons sugar and 1 tablespoon tap water until berries are bubbling and thickening. Whisk 1 teaspoon tap water with 1 tablespoon cornstarch and whisk into blueberry sauce. Let cool.
When raspberries in piecrust have cooled, pour blueberry sauce over fresh blueberries in center of pie. When sauce has set a bit (about 15 minutes), remove the ring. Chill to set, about 40 minutes.
Decorate pie with White Chocolate Stars. Moisten backs of stars lightly to adhere.