Garten's recipe had just five ingredients (plus salt and black pepper), and I already had most of them in my cupboard. It just called for plain flour, eggs, butter, an onion, and potatoes.

Mary Berry uses one egg and one egg yolk rather than two eggs. This makes the batter richer and tastier as the yolk offers tasty, rich fats and contains an emulsifying factor called lecithin. Lecithin ...