01 -
In a bowl, sift together the cake flour, baking powder, salt, and nutmeg.
02 -
In the bowl of a stand mixer fitted with a paddle attachment, beat the butter and sugar together until sandy. Add the egg yolks and mix until light and thick.
03 -
Add the dry ingredients to the mixing bowl in 3 additions, alternating with the sour cream, ending with the flour. Mix for 30 seconds on low speed or until the dough is smooth but slightly sticky.
04 -
Cover with plastic wrap and chill for 1 hour, or until firm.
05 -
On a floured surface, roll out the dough to about 1/2 inch thickness. Use a doughnut cutter or two differently sized biscuit cutters to cut out as many donuts as possible. Refrigerate while you heat the oil.
06 -
Pour 2 inches of canola oil into a heavy-bottomed pot with a deep-fry thermometer attached. Heat to 325°F.
07 -
Fry the doughnuts a few at a time. Cook on each side for about 2 minutes or until golden brown. Let drain on a paper bag to soak up excess grease.
08 -
Mix the powdered sugar, corn syrup, salt, vanilla extract, and hot water in a bowl with a whisk until smooth.
09 -
Immerse each doughnut into the glaze and place on a wire rack above a sheet pan to catch excess glaze. Let sit for 20 minutes until the glaze is set.