Step 1 In a large bowl, sift together the flour, baking powder and cocoa powder. Set aside.
Step 2 In the bowl of a stand mixer, or in a large bowl using a hand mixer, beat together the canola oil, eggs and vanilla. Add the sugar, mixing until well blended.
Step 3Gradually add the flour mixture to the egg mixture, mixing at low speed until it is smooth (if using a hand mixer, some of this may need to be done by hand with a large spoon). Stir in the white chocolate chips.
Step 4Keep the dough in the mixing bowl and place it, covered, in the refrigerator for at least an hour to chill thoroughly.
Step 5When the dough is cold, heat the oven to 350 degrees. Line a cookie sheet with parchment paper.
Step 6Wet your hands with cold water and form the dough into 2 fat and long logs about 12 inches in length, 3 to 4 inches wide and one-half to three-fourths inch in diameter. Place them side by side on the cookie sheet, but leave space between them to give them room to expand while baking.
Step 7Bake for 25 minutes at 350 degrees.
Step 8Remove the tray from the oven and reduce the temperature to 300 degrees.
Step 9Cool the logs on the cookie sheet for about 20 minutes. Then cut the logs into 1/2-inch slices and, keeping them upright, arrange them on the cookie sheet so there is a little space between them.
Step 1 0Return the cookie sheet to the oven and bake the slices for another 15 minutes to dry them out.
Step 1 1Cool completely before packing in an airtight container. I usually double-bag these and freeze them. (You can zap 1 or 2 at a time for 20 seconds in the microwave.)