The levening of yorkshire pudding is the eggs. As such, it will "rise" by only a small amount. What gives the pudding its texture and volume is the rappid plunge into oil that is near or at the smoke point. Rappidly pouring in the batter will cause it to swirle around and up the sides of your muffen tin or roasting tray. In this, it is being cooked to the shape characteristicly know as yorkshire pudding. The additional 10 minutes alows for cook through (not expansion) of the batter, and for some browning to occure. But otherwise, it is cooked almost as soon as it hits that oil.Note of caution: DON'T SPLASH YOUR BATTER. Grease fires are not fun!! Nor are oil scalds.
I have, off and on, watched this ladys web site for some years now (and she appears to be hosted here, looks like she's been bitten by fame again argg usage stats!!). She is pretty bang on, and sometimes is more directly informative than a lot of other such sites.http://www.britannia.com/cooking/rec...repudding.html