Old fashioned cake donuts with vanilla glaze

Sift the cake flour into a medium bowl.

Add the baking powder and the kosher salt and sift.

In a large bowl, beat the room temperature butter with the sugar on high about a minute with a hand mixer, until light and fluffy.

Add the egg yolks and mix about two minutes, until the butter and sugar come together into a creamy paste.

Mix in the sour cream, which adds moisture, holds the shape because it is thick, and brings acid for a more tender crumb.

Add the flour mixture to the wet on the lowest setting until almost combined, then fold with a spatula just until the flour streaks disappear. Overmixing activates the protein in the flour and makes them tough.

Cover and refrigerate at least an hour, or overnight.

Put two inches of oil in a big heavy bottomed pot with a thermometer and set it over medium heat.

Flour the work surface liberally, turn out the dough, flour the top and the rolling pin, and roll out to half an inch: too thick and it will not cook through, too thin and it will dry out and not puff.

Flour a three inch cutter and cut out rounds onto a parchment lined baking sheet; re-roll the scraps. Cut the centres with a one inch cutter.

Gently score each donut four times around the outside, so it puffs and segments and gives more surface area for the crisp edges and the glaze.

Fry in batches of two or three, keeping the oil between 330 and 340F and adjusting the heat as the cold donuts drop the temperature. Do a test batch of one first.

Fry about two minutes on the first side, until they float back up, then flip and fry two minutes more, or longer for a deeper gold.

Whisk the powdered sugar, water, vanilla and a pinch of salt into a very thin, watery coating glaze, not a drizzling consistency.

Dip the warm donuts halfway, shake off the excess and let the glaze set.