Gather your ingredients.
In a large bowl, add your cake flour and baking powder.
Mix in your salt.
Add in your nutmeg.
In the bowl of a stand mixer, add your sugar.
Add your butter.
Add your egg yolks and mix until combined.
Add your dry ingredients to the wet ingredients in 3 additions.
Alternate with the sour cream and end with the flour. The dough will be thick and sticky. Cover with plastic wrap and chill dough for 1 hour.
On a floured surface, roll out dough to about 1/2 inch thickness. We rolled ours out a little thinner that so make sure to roll out to your preferred donut thickness!
Using a doughnut cutter or, in our case, a large measuring cup, cut out as many donut as possible.
We used a very small bowl to cut out the donut holes.
In a large bowl add your powdered sugar.
Add vanilla extract.
Add corn syrup.
Add hot water.
Mix together until smooth.
Pour 2 inches of canola oil into a heavy bottom pot. Heat to 325 F. Fry your doughnuts a few at a time for about 2 minutes inch side. Be careful not to let them burn! Let cool on a wire rack.
Immerse each doughnut into the glaze. Place back on the wire rack. Have the wire rack on top of a sheet pan to catch any extra glaze. Let sit for 20 minutes, or until glaze is set. Enjoy!
Recipe inspired by: http://www.handletheheat.com/old-fashioned-sour-cream-doughnuts/