In a large bowl whisk together the flour, baking powder, baking soda, nutmeg and salt. Set aside

In a separate large bowl using a stand or hand-held electric mixer beat together the egg, egg yolk and sugar on medium speed. Once combined, turn off the mixer and stir in the vanilla and melted butter.

Using a large rubber spatula or wooden spoon fold in half the flour mixture, followed by the buttermilk. Mix briefly with the electric mixer on low to fully combine. Repeat with the remaining flour mixture & buttermilk until everything is combined. The dough will be thick.

Flour a flat surface, and roll out the dough using a floured rolling pin until the dough is approximately ¼ to ½ inch thick. Cut into doughnuts using a doughnut cutter. Form a ball with the left over pieces of dough, roll-out again and cut doughnuts from the remaining batter.

Clip a deep fry/candy thermometer to the inside of a heavy-bottom Dutch oven pot with high sides. Pour oil into the bottom of the saucepan so its about 2-inches deep. Heat the oil on medium-high heat until a temperature of 375F degrees is reached. Carefully place 2 or 3 doughnuts into the saucepan. Fry the doughnuts for about 60 seconds on the first side. Then flip using a heat proof tool - such as the end of a wooden spoon or tongs, and fry on the second side for about 60 seconds. Remove from the hot oil using a large slotted spoon, the end of a wooden spoon or tongs and place on a flat surface lined with clean paper towels. Allow the oil to return to 375F before continuing with process with the rest of the doughnuts. Doughnut holes will take about half the time, or about 30 seconds per side. After frying the first set of doughnuts and allowing them to cool for a few minutes - break the doughnut open to ensure it's cooked throughout and adjust your frying time accordingly.