Gregg Wallace visits the factory making 432 million crumpets every year. Crumpets are a British classic made from a precise combination of ingredients, using some clever chemistry to create their famous ‘holey' texture.Cherry Healey is learning the science of how to make the perfect batter for pancakes and visits a factory in Manchester that makes another British favourite, Eccles cakes, which are shipped all over the world.Ruth Goodman reveals the long journey of how crumpets got their rise and eventually their bubbles, and traces the history of Britain's obsession with toasting baked goods.