Beat eggs and sugar together until lemon colored and smooth. Add 2 cups of flour, one tablespoon at a time, allowing it to mix thoroughly. Next add the baking powder and 1/3 of the oil, drizzling it slowly in, again allowing it to mix thoroughly.
Just like before, add 2 more cups of flour, then vanilla, then 1/3 of oil. Then, add 1/2 of remaining flour (about 1 cup), and the rest of the oil. Add just enough of the remaining flour to form a thick dough that will slowly run off the beaters when you stop and lift the mixer. Be careful, as this is a very heavy dough and could damage your mixer's motor if you try to run it too fast. Usually the recipe uses 5-5 1/2 cups of flour total.
Mix in nuts with a wooden spoon. Pour onto 2 lightly greased jelly roll pans, as a large loaf in the center of each pan. Bake for 20 minutes, moving the pans from one rack to the other at the 10 minute mark.
When finished, carefully remove the loaf from the pan and place on cooling racks. You can cut the loaf in half to keep it from breaking. Cut each loaf into 3/4" slices, and place each slice back onto the pans, raw side up. Brown for 10-15 minutes (still at 350 degrees) on each side. Cool on racks.