The Secret to Smooth Doughs and Fluffy Bread Is Already at Hand

Just-boiled water has long played a role in making pie crusts, milk breads and more shine, across cultures and cuisines. But how does it work?

If there’s a quintessential dish from the chef Nadiya Hussain — the “Great British Baking Show” winner who has since found huge success — it’s probably the samosa pie with the turmeric crust from the very first episode of her solo cooking show “Nadiya’s Family Favourites.” Meant to be unmolded for maximum impact, the pie stands impossibly tall and doesn’t crumble, even when sliced. Ms. Hussain likes to wrap the whole golden thing in parchment paper and take it to picnics, passing out fat, perfect wedges to family and friends. Luckily, the trick to it — an old-fashioned British pie crust Ms. Hussain makes with flour, shortening and water at a boil — is just as easy.