Preheat oven to 350. Coat an 11 x 17 inch baking sheet with nonstick spray.
Whisk together sugar, brown sugar, oil, pumpkin puree, eggs, and vanilla. Sift flour, baking powder, cinnamon, salt, baking soda, ground ginger, cloves and nutmeg into pumpkin mixture. Whisk mixture into wet ingredients til mixed. spread batter onto prepared baking sheet.
Bake bars til a toothpick inserted in center comes out clean, about 20minutes. Transfer pan to a rack and let cool. For garnish, chop cranberries, crystallized ginger and pecan pieces together.
Melt white chocolate in microwave on high 1 to 2 minutes. Stir til smooth. Beat cream cheese and butter with mixer on high speed til smooth. add melted chocolate and beat to mix. add powdered sugar and beat on low speed til smooth. Spread frosting over cooled bars and top with garnish. Cut into squares to serve.