These donuts are cakelike, but have a very light, tender and airy texture. I achieved this by using both baking powder and baking soda, plus active dry yeast. They are perfect when they are a little bit warm when eaten. You won't be able to stop at eating just one!
QUICK-BREAD RECIPE HELP

These doughnuts can also be filled after frying! I also created a technique whereby you can fry them already filled, which is a great time-saver, and we show you how. However, you need to use certain fillings that can withstand the heat.
Boston Cream Pie Filled Doughnuts – Filled After Frying

Lemon Meringue Pie Doughnuts – Filled Before Frying

OLD-FASHIONED BUTTERMILK CAKE DOUGHNUTS
INGREDIENTS
3 1/4 cups unbleached all-purpose flour, plus extra; spoon into measuring cup and level to rim
3/4 cup sugar
1 1/2 teaspoons freshly grated nutmeg
1 teaspoon baking powder
1/2 teaspoon baking soda
1 teaspoon salt

1/4 cup sour cream

1 1/8 teaspoons active dry yeast

3/4 cup plus 2 tablespoons buttermilk
1 large egg
3 large egg yolks
1 tablespoon vanilla extract

For Frying:
Deep heavy-bottomed saucepan that holds and maintains heat, filled halfway with fresh vegetable oil; canola oil is fine to use
Deep Fry Thermometer

For decorating:
1/2 cup non melting icing sugar or powdered sugar

Special Items:
one 2 1/2-inch dough cutter or a 2 1/2-inch round cutter to make the doughnuts
one 1/2-inch round cutter to make the doughnut holes

INSTRUCTIONS
STEP I: MAKE THE DOUGHNUT DOUGH
1. In a large mixing bowl, sift to combine the measured flour, sugar, nutmeg, baking powder, baking soda, and salt.
Make a well in the center.
Set aside.

2. In a small stainless-steel bowl set over a pot of gently simmering water, heat the sour cream until just warm, stirring the entire time.
Take care that it does not burn.
SARAH SAYS: With an Instant Read Thermometer, the sour cream's temperature should measure between 100 – 115 degrees F.

3. Place the yeast in the flour well.

Pour the warmed sour cream over the yeast. Let sit for about 1 minute.
SARAH SAYS: With an Instant Read Thermometer, the sour cream's temperature should measure between 100 – 115 degrees F.

4. Pour the buttermilk, whole egg, egg yolks, and vanilla extract into the well.

Whisk together the liquid ingredients in the center of the flour well.

5. Using one hand, gradually draw in the dry ingredients.

The mixture should be fairly smooth before you draw in more flour.

The mixture should be fairly smooth before you draw in more flour with your hand.

Mix until it is completely incorporated and forms a very sticky dough. Wash and dry your hands and dust them with flour.
NOTE: Prepare to get sticky! This IS a very sticky dough!

STEP II: SHAPE THE DOUGHNUT DOUGH AND FRY
Prepare the Frying Fat:
1. In a large, heavy-bottomed saucepan, heat the vegetable oil, under medium-high heat, to 375 degrees F, as measured with a deep fry thermometer.
Keep on the stovetop with the burner on, adjusting as necessary to retain a constant temperature.
Before you begin frying, have everything you need near the stove: the shaped doughnut dough, heatproof tongs or a slotted spoon, and paper towels, set on a large sheet pan, for draining.

Shape the Doughnuts:
1. Sift an even layer of flour onto a work surface.
KELLY SAYS: I like to use a silpat, nonstick mat as my work surface. I always sift flour onto it so there are no lumps.

2. Scrape the sticky dough out of bowl onto the floured work surface.

Sift more flour over the dough.

3. Working quickly, gently pat the dough into an even 1/2-inch thickness.

Take care not to slap or pound the dough because you do not want to condense it.

4. Dip the 2 1/2-inch round cutter in flour and, cutting as closely together as possible, cut out the doughnuts.

5. Then, with a 1/2-inch round cutter, cut out the holes in the center of the 2 1/2-inch round cut circles of dough.

Place holes and doughnuts on a floured surface.

6. Working quickly, gather scraps of dough together, pat into 1/2-inch thickness, and cut out remaining doughnuts and holes.

Fry:
SARAH SAYS: Always check the oil's temperature before frying every doughnut batch – it should be 375 degrees F, as measured with a Deep Fry Thermometer.
1. Fry doughnuts by dropping them into the hot oil, no more than three donuts at a time.

2. Fry each one for 1 to 2 minutes on each side, until lightly browned and thoroughly cooked.

Remove and drain on paper towels.

3. Check the oil's temperature. Fry another doughnut batch. Drain on paper towels when lightly browned and thoroughly cooked.
Repeat until all of the doughnut dough has been cooked.

4. Check the oil's temperature.
Then, fry the holes, by dropping them into the 375 degrees F, as measured with a deep fry thermometer, no more than six at a time.

Finishing Touches:
1. Sift a layer of non melting icing sugar or powdered sugar over doughnuts and holes.
NOTE: These donuts are very light, tender and airy. Perfect when they are a little bit warm when eaten.

SERVE AND STORAGE
Fried foods, such as doughnuts, are best eaten right away, if not within an hour after they are made. Store in a paper or plastic bag if necessary.
If the filling is perishable, refrigerate.