Preheat your oven to 350 degrees and line a baking sheet with parchment paper. Beat the butter and granulated sugar with an electric mixer.
Next add in the vanilla extract, orange zest, and eggs. Mix until all the ingredients are fully incorporated.
In a separate bowl, whisk together the all purpose flour, white whole wheat flour, baking powder, and salt.
Slowly add the flour mixture into the first mixture. Use an electric mixer on a low speed until all ingredients are fully combined, forming a dough.
Mix in the dried cranberries. You can combine them by using an electric mixer or by simply folding them in with a sturdy spatula.
Cut the dough in half. Form each half into a ball. Next, shape each ball into a log that is approximately 8 inches long.
Place the logs onto the baking sheet lined with parchment paper. Use your hands to flatten each log until they are about 3/4 inches thick.
Sprinkle each log with turbinado sugar.
Bake for 20-25 minutes until the logs are golden brown and the dough is firm.
Let the logs cool for 30 minutes on the baking sheet.
Use a knife to cut the logs on a diagonal into the shape of biscotti. Do not move the knife back and forth to cut through the logs, but rather press straight down so that the biscotti pieces are clean and uniform.
Place the cooled biscotti pieces cut side up on the same baking sheet. Bake for 12-15 more minutes until they harden and dry. The center of the cookies should be slightly soft.
Let the cookies completely cool.
In a microwave safe bowl melt the Baker's White Chocolate bars. Use a fork to drizzle each cookie with white chocolate.
Place the biscotti in a cool room so that the white chocolate easily hardens. If you need to, you can let them sit overnight and then place them in an airtight container the next morning.