In a large bowl, whisk the oil, sugar, eggs, vanilla until blended. Gradually add the flour mixture to the egg mixture, mixing until well blended.
Transfer dough to prepared cookie sheet; use damp hands to shape into two 12×2-inch rectangles (about 3/4 inch high). Bake 23-25 minutes until golden brown and set at center. Transfer the cookie sheet to a rack to cool for about 15 minutes or until it can be easily handled. Lift the biscotti off sheet onto a cutting board, peeling off the parchment. Using a large, sharp knife, cut it crosswise into slices about 1/2-inch thick. Discard the parchment.
Place biscotti back on sheet with a cut side down. Bake 12-14 minutes until the biscotti golden & dry. Transfer biscotti to a rack and cool completely (they’ll crisp as they cool).