The UK's Royal Society of Chemistry has decreed that a staple of English cuisine, the Yorkshire pudding, which accompanies the classic dish of roast beef, must be 4 inches high. Its ad hoc regulations concerning the whisked flour, milk, and egg delicacy could ultimately be adopted internationally. Yorkshire "puds" are essentially an aerated savory crepe commonly eaten with the Sunday roast but recipes for their creation vary wildly and often fail to rise to the occasion. The RSC's recipe created with the assistance of Yorkshireman and chemistry prof John Emsley in Cambridge specifies the required starting materials, mixing ratios and reflux time for maximum yield. As to stereochemistry, this presumably depends on the direction of rotation of the oven's fan.