For the donuts:
2 1/4 cup (255 grams) cake flour
1 1/2 teaspoons baking powder
1 teaspoon salt
1/2 teaspoon ground nutmeg
1/2 cup sugar
2 tablespoons butter, at room temperature
2 large egg yolks
3/4 cup sour cream
Canola or vegetable oil, for frying
For the glaze:
3 cups powdered sugar, sifted
1 1/2 teaspoons corn syrup
1/2 teaspoon vanilla extract
1/2 cup hot wate
Sift dry ingredients (cake flour, baking powder, salt, and nutmeg) in a smaller bowl. Set aside.
In a large bowl, combine butter and sugar on a low speed until light and fluffy. Add the egg yolks and mix together on a medium speed. Add half the dry ingredients, blend. Add the sour cream, blend. Add in the rest of the dry ingredients and blend until the dough is well-combined. Place dough in greased bowl and cover with plastic wrap. Chill for an hour.
Place chilled dough on a floured surface. Roll out to about 1/2 inch thickness. Cut the donut shapes with pastry cutters or use a roughly 3-inch cup and a roughly 1 1/4 inch shot glass. (BONUS: You can save the insides for donut holes or combine them, roll out your dough again, and make more full-sized donuts). Lightly score three lines in each donut, forming a triangle.
Heat oil to 325°F. Carefully place the donut in the oil scored side up. Let the donut float to surface and cook for about 15 more seconds. Flip and fry 90 seconds. Flip again and fry for 75 more seconds (or until both sides are golden brown).
ANOTHER BONUS: If you decide to make donut holes, cut the frying time in half. Set on paper towels to soak up excess oil and cool down.
Create your glaze by combining the powdered sugar, vanilla extract, corn syrup, and hot water until it becomes smooth. (Cover when not using immediately.) Dip the top of each donut in your glaze and set on a drying rack to allow glaze to dry and any extra to drip off.
Store any leftovers in an airtight container in the fridge for up to one week. You can also make the dough the night before, store it in the fridge overnight, and finish making the donuts in the morning. Enjoy!