Heat oven to 450°F. In ungreased 10- or 9-inch tart pan with removable bottom, press pie crust evenly in bottom and up side of pan. Generously prick crust with fork.
Bake 6 to 9 minutes or until golden brown. Reduce oven temperature to 325°F. Cool crust 15 minutes.
Meanwhile, reserve 2 pear halves for garnish; refrigerate. Slice remaining pear halves; place in small bowl. Add raw sugar, 1/2 teaspoon of the ginger and bread crumbs; toss gently to coat. In medium bowl, beat cream cheese and mascarpone with electric mixer on high speed until smooth. Add condensed milk, butter, remaining 2 teaspoons ginger, 1 whole egg and 1 egg yolk; beat on medium speed until well blended. Spread 1 cup filling over cooled crust; arrange pear slices on top. Spread remaining filling over pears.
Bake at 325°F 40 to 50 minutes or until set and golden brown around edge. Cool 30 minutes.
In small microwavable bowl, microwave 1/3 cup whipping cream and chocolate chips on High 1 to 2 minutes, stirring every 30 seconds, or until smooth. Stir in corn syrup until well blended. Spread over cooled tart. Refrigerate 1 hour 30 minutes or until set.
Cut reserved pear halves into 12 slices. Remove side of pan. To serve, cut into 12 wedges. Top each wedge with 2 tablespoons whipped cream, 1 pear slice and 1 teaspoon walnuts. Store covered in refrigerator.