To make the dough:

Cup of Yum
1. In a large bowl, combine the flour, baking powder, baking soda, salt, and nutmeg. Set it aside.
2. In the bowl of a stand mixer fitted with the paddle attachment, cream the butter and sugar for 2 to 3 minutes until light and fluffy.
3. Mix in the egg and vanilla until fully combined.
4. Scrape down the bowl and add half of the dry ingredients. Mix on low speed until barely combined, then mix in the sour cream.
5. Add the rest of the dry ingredients, and mix until just combined.
6. Cover the bowl and place it in the fridge to chill for at least 1 hour or overnight.

To fry the donuts:

1. Just before rolling out the dough, fill a Dutch oven or heavy-bottomed pot with enough vegetable oil to cover 2 inches (5 centimeters). Heat the oil over low-medium heat and bring it to 350˚F (180˚C).
2. Place a wire rack over a paper towel-lined baking sheet.
3. On a separate baking sheet, cut out twenty-eight 3-inch (8-centimeter) parchment squares for the donuts.
4. Roll the dough out between two pieces of well-floured parchment paper to 1/2 inch (1.3 centimeters) in thickness.
5. Brush away any excess flour.
6. Use well-floured 2 1/4-inch (6-centimeter) and 1/2-inch (1.3-centimeter) round cutters to cut out as many donuts as possible and place each on a parchment square. Reroll the dough and cut out more donuts as needed.
7. Use the parchment squares to gently lower two to three donuts into the hot oil.
8. Fry the donuts for 2 minutes on the first side, then flip over and fry for 2 minutes until golden.
9. Transfer the donuts to the wire rack to cool completely.
10. Wait a couple minutes for the oil to come back up to 350˚F (180˚C), then continue frying the donuts.

To coat:

1. Once the donuts have cooled completely, quickly toss each of them in confectioners' sugar.
2. Be careful not to handle them too much or the confectioners' sugar will melt.