Preheat oven to 350° (325° for dark or glass pan). Prepare a 10 x 15 pan by lining it with parchment paper or spraying with non-stick spray. You can use a 9 x 13 pan instead, but the cooking time will be slightly longer (see note below).
BARS: With an electric mixer, beat together the softened butter and sugars for 3-5 minutes until light and fluffy. Add the orange extract and eggs and mix until just combined. Add the flour, baking powder and ginger (which are combined in a bowl ahead of time). Add the cranberries, white chocolate chips and chopped crystallized ginger, stirring until just combined.
Spread the thick batter into the prepared pan. Bake at 350° for 20-24 minutes until light brown at the edges and a skewer inserted in the center tests clean. Don't over bake or your bars will be dry and crumbly. Let it cool completely. (NOTE: for a 9 x 13 pan, the bars will be thicker and will take 26-28 minutes to bake).
FROSTING: Blend cream cheese and butter until fluffy. Add orange extract and confectioner's sugar and beat until frosting is fluffy and spreadable (adding 1 Tbs of milk if needed. Spread evenly over the COOLED bars.
GARNISH: Use a zester to remove the rind from an orange. Sprinkle zest over the frosted bars. Chop 1/3 cup Craisins coarsely; sprinkle over frosted bars.
DRIZZLE: Mix white chocolate and oil in a glass measuring cup. Microwave 1 minute; stirring every 15 seconds until melted. Use a fork or put the chocolate into a small ziploc bag with the corner snipped off to drizzle the white chocolate diagonally across the bars.
Allow 1 hour for the white chocolate to set before cutting. To make the Starbucks' signature triangles, cut into 24 large squares (6 by 4 cuts with the knife). Then cut each square diagonally to create triangles.