I love the tiny lift from that pinch of nutmeg and the tangy note from the sour cream and buttermilk. You don’t have to wait hours for these to rise and they are tasty. I recommend cutters for a standard size doughnut. If you like smaller, use smaller cutters! Here we roll the doughnuts simply in sugar. Add spices if you like. Add cocoa powder. Make a simple glaze and dunk instead. I like to roll some in spices and keep some plain and do a mixed platter. My absolute favorite way to serve them: I roll them in powdered sugar with an excessive amount of cinnamon. If you like spices, add some to your powdered sugar.
Pour the oil into a large saucepan (5-6 quart capacity). Prepare a baking sheet fitted with a kitchen towels and a slotted spoon to remove and place the doughnuts as they emerge from the hot oil.
Mix the dry ingredients:
in a large bowl, sift together the all-purpose flour, cake flour, sugar, baking powder, baking soda and nutmeg. With your hand, make a hole in the center of the dry ingredients and pour the yeast in the center.
Make the dough:
Place the sour cream in a heatproof bowl and warm gently over a pot of simmering water, like a makeshift double boiler, 2-3 minutes. When warmed, remove the bowl from the heat. Pour the sour cream directly over the yeast and allow the sour cream and yeast to sit 2-3 minutes. In a medium bowl, combine the buttermilk and vanilla with all of the eggs. Gently stir the dry ingredients in with the sour cream yeast mix. Stir the wet ingredients into the mix as well.
Cut the doughnuts:
Sift a generous layer of flour onto 2 baking sheets. Flour a clean flat surface and turn the dough out. It will be sticky. Sift more flour on top of the dough, flour your hands and pat the dough until about ¾ inch thick. Dip the cutter in flour so it won’t stick. Cut a round and gently transfer to the floured baking sheets. Flour the cutter between each doughnut. Cut the rounds close together to avoid making too many scraps. Gather the scraps and roll into a ball.
Dip the smaller cutter in flour and cut a round out of the center of each doughnut to make the “hole”. Save the small dough holes. Let the doughnuts rest 8-10 minutes.
Heat the oil:
In a large, heavy-bottomed pot, heat the Canola oil over medium low heat. Use a thermometer to monitor the temperature until the oil reaches 350F.
Fry and eat:
Use a slotted spoon to submerge 5 doughnuts in a single layer in the hot oil. Fry until the bottoms are browned, 3-4 minutes. Use a slotted spoon to carefully turn each doughnut on their second side and fry an additional 3-4 minutes until browned. Remove and drain on the sheet fitted with kitchen towels. Repeat with the remaining doughnuts. Take care to allow the oil to reheat between batches. Flatten and cut the scraps for a few additional doughnuts. Fry the doughnuts holes as well. Cool for at least 15 minutes then toss in the powdered sugar.