Prepare pastry shell. Add dry ingredients to food processor. Pulse until mixed. Cut butter and cream cheese into small pieces and add to food processor. Pulse 5 or 6 times to remove butter particles to pea-size and coat with flour. Combine water with yolk and add to food processor. Pulse until dough begins to pull together. Add extra teaspoon of ice water if dough is dry. Form dough into a circle, dust with flour and wrap in waxed paper. Allow to rest in refrigerator at least 30 minutes. Roll out dough to 11-inch circle. Fold in quarters and unfold in pie pan. Ease dough into comers, being careful not to stretch it and trim dough even with edge of pan. Prick bottom of pastry shell with a fork and freeze for 15 minutes.
Preheat oven to 425F. Line pastry shell with foil weighed down with baking beans. Bake for 8 minutes. Remove foil with beans. Sprinkle pastry shell with 1 tablespoon of sugar and bake an additional 8 minutes or until light golden-brown. Remove from oven and cool completely.
To prepare grapefruit curd, strain grapefruit juice into small non-reactive saucepan. Boil over medium-high heat until reduced to 1/4 cup. Add rinds and set aside. In a double boiler or metal bowl set above simmering water, melt butter. Whisk eggs into butter, followed by sugar, grapefruit juice, rum and salt. Whisk continuously until thick and the whisk leaves a trail in the curd (about 15 minutes). Strain curd to a bowl and allow to cool to room temperature. Sprinkle blackberries with 1 tablespoon of the sugar and macerate 1/2 hour.
Strain blackberry preserves of seeds and spread 1/3 cup into bottom of pastry shell. Spoon curd over preserves and level. Place blackberries upright on top of curd, forming concentric circles. Warm remainder of preserves and lightly brush on tops of berries. Just prior to serving, dust with the other tablespoon of powdered sugar.
Cajun Country -- New Iberia, Louisiana