The night before add brandy to prunes in an airtight container - cover and let sit overnight.
Preheat oven to 325 degrees
Mix butter, cream cheese and salt in large bowl with hands till crumbly. Add flour and mix till just combined.
Turn out onto a lightly floured surface and divide in half. Shape each half into a disk; wrap each in plastic and refrigerate about 4 hours or overnight.
Stir together breadcrumbs and 1/2 cup of sugar and set aside. In a separate bowl stir together remaining 3 tbsps of sugar and add the cinnamon, set aside.
To make the filling: Drain the prunes and puree in a food processor until smooth. Transfer to a small bowl, stir in breadcrumbs and sugar. Refrigerate till ready to use (can be done up to one day before).
Roll 1 disk to 1/8 inch thick. Cut out a 12" circle. Brush a 1" wide border with the beaten egg. Put half the prune filling in the center and sprinkle 1/2 cup breadcrumb mixture over the filling. Cut into 16 wedges. Starting at an outside edge of each wedge, roll up into a crescent shape. Space 1" apart on a parchment lined baking sheet.
Brush with the beaten egg and sprinkle with the cinnamon-sugar mixture. Repeat this process with the remaining disk and filling. Refrigerate rugalach until cold - about 2 hours.
In the pre-heated oven bake rugalach till golden brown - about 40 minuets. Let cool completely on wire racks. Can be stored in airtight containers at room temps for up to 3 days.