Adjust rack to center position and heat the oven to 350 degree. Line a cookie sheet with wax or parchment paper.
Place the flour, sugar, baking powder, salt and white chocolate chips in a large bowl and stir to combine.
In a small bowl combine the eggs, butter and vanilla and whisk to fully combine. Make a well in the center of the dry ingredients and pour in the egg mixture. Using a rubber spatula, mix to combine until a rough dough forms. Don't be concerned if the dough is crumbly- this is typical of biscotti dough. It will come together in the next step.
Dump the dough onto a work surface and knead a couple of times until the dough comes together, adding extra flour sparingly and only if necessary. Start to form the dough into a big, fat cigar and cut it in half. Form each half into a cigar about 1 inch thick, 2 inches wide and about 12 inches long. Place them onto the cookie sheet and lightly press with fingers to slightly flat cigars.
Bake for 25 minutes reversing the pan halfway through. The bars will be firm to the touch and just slightly browned. Remove from the oven and lower the temperature to 300 degrees. Let the cookies cool on the cookie sheet for 15 minutes.
Remove cookies to a cutting board using two spatulas. Using a serrated knife, slice the bars on an angle about 1/2 inch thick to form the biscotti. Lay them back on the cookie sheet with either cut side down and place back in oven for 12 minutes. Turn each cookie to expose the other cut side and place in oven for another 12 minutes. Let cool on a rack to room temperature. Place cookies in an airtight container.