Prepare the Dough:

Mix Dry Ingredients:

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

Combine Wet Ingredients:

In a separate bowl, whisk together the melted butter, eggs, buttermilk, and vanilla extract.

Form the Dough:

Gradually add the wet ingredients to the dry ingredients, stirring until a soft dough forms. Avoid overmixing.

Chill the Dough:

Wrap the dough in plastic wrap and refrigerate for at least 1 hour to make it easier to handle.

Shape the Doughnuts:

Roll Out the Dough:

On a lightly floured surface, roll the dough to about 1/2-inch thickness.

Cut the Dough:

Use a knife or dough cutter to cut the dough into bar shapes, about 4 inches long and 1.5 inches wide.

Fry the Doughnuts:

Heat the Oil:

Heat vegetable oil in a large pot or deep fryer to 350°F (175°C).

Fry:

Fry the bars in batches for 1-2 minutes per side, or until golden brown. Use a slotted spoon to transfer them to a wire rack lined with paper towels to drain.

Make the Glaze:

Prepare the Glaze:

In a medium bowl, whisk together the powdered sugar, buttermilk, and vanilla extract until smooth. Adjust the consistency by adding more buttermilk if needed.

Glaze the Doughnuts:

While the doughnuts are still warm, dip each one into the glaze, allowing the excess to drip off. Place them back on the wire rack to let the glaze set.