Preheat oven to 350 degrees. Place flour, salt, sugar and baking powder in bowl of large food processor. With machine running, add butter one stick at a time (cut into chunks) until mixture resembles coarse meal. Don't over-process or it will start to get gummy. Place in large bowl. Make well in center. Combine liquids (including beaten egg) in measuring cup and pour into well. Mix with hands just until dough forms. Over kneading can result in a tough crust. Divide dough into four equal parts; roll into balls. Use one ball, freeze the rest. With rolling pin, roll out on floured surface. Put in 9-inch pie plate; crimp edges. Place in freezer while you prepare filling. For Filling: Remove crust from freezer and cover bottom with pecans and cranberries. Place the syrup and sugar in saucepan and bring to full rolling boil. Remove from heat. Add butter and stir until melted. Transfer to clean mixing bowl. Beat in eggs, flour, and rum with electric mixer. Add syrup-sugar mixture a little at a time (a steady drizzle), mixing constantly. Pour the liquid over the pecans and cranberries in crust. Bake for 45 minutes, or until set.