In the bowl of a food processor, combine flour, sugar, and salt; blend for five seconds. Add margarine and pulse until mixture is crumb-like.

Add two tablespoons whipping cream and egg yolk. Blend until moist clumps form, adding more cream by teaspoonfuls if dough is dry.

Gather dough into a ball; flatten into a disk. Wrap and chill one hour. (Dough can be made two days ahead. Keep in the fridge.)

Roll out dough on lightly floured surface to a 13-inch (33-centimeter) circle. Transfer to 9-inch (23-centimeter) diameter tart pan with removable bottom. Pierce crust all over with fork; refrigerate one hour.

Preheat oven to 400 degrees Fahrenheit (200 degrees Celsius). Bake crust until golden, about 20 minutes. Allow crust to cool completely.

In a medium pot, place all ingredients except margarine. Stir constantly over medium heat until mixture thickens — do not leave for a second! (l use a whisk for this.)

Remove from heat. Add margarine and stir until melted. Cool slightly. Pour into pie crust.

Decorate top with fresh blueberries.

Grate pareve white chocolate over all. Refrigerate until using.