Marinate the cranberries in the Grand Marnier overnight.
Preheat oven to 350° F.
In a medium bowl, sift the flour, baking powder and salt together. Using your fingers, rub the butter into the flour mixture until the texture is sandy. Stir in the cranberries.
Make a well in the center of the flour mixture and add the cream and sugar, stirring until the sugar is dissolved. Mix the flour and the cream together lightly. Divide dough in half.
On a lightly floured surface, roll each half out to a circle 1/4 inch thick. Cut each circle in four wedges. Place wedges 1 inch apart on a greased baking sheet. In a small bowl, combine egg and water and brush over wedges.
Bake 15 to 20 minutes or until golden brown.Makes 8 scones