Preheat oven to 350F and coat bottom of a 13" x 9" baking dish with 2 Tbsp butter. Cut a large pocket in each bread slice without cutting all the way through. Stir together ricotta cheese, powdered sugar and cream cheese in a small bowl. Spread equal amounts in each bread pocket and top with equal amounts of prunes; press bread lightly to seal. Whisk together half and half, sugar, vanilla and eggs in a shallow dish. Dip each bread slice in the mixture, turning to coat both sides. Place in buttered dish, overlapping slightly so that the rounded tops are raised a bit.

Pour any remaining egg mixture over the top and drizzle with remaining butter. Let stand for 30 minutes or until egg mixture is absorbed by the bread, tiping pan occasionally. Bake for 30-35 minutes, or until lightly browned. Place on four plates and sprinkle with powdered sugar, chocolate chips and orange zest, if desired.