A spike in sales of certain ingredients at Waitrose proves that Delia Smith’s influence over home cooks remains as strong as ever.

Smith, whom Waitrose has recruited along with chef Heston Blumenthal for its marketing campaign, created a leek, potato and cheese soufflé to help launch the supermarket’s latest series of recipes.
Following the publication of the recipe, sales of soured cream went up by 96%, Parmesan cheese by 320% and Cheddar by 219% over the previous week, while sales of trimmed leeks and Désirée potatoes both rose by almost 200%.
Waitrose says the recipe helped boost total weekly sales at Waitrose, up 5.5% over the same week last year.