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

In another bowl, combine the buttermilk, melted butter, egg, and vanilla extract.

Pour the wet mixture into the dry ingredients and stir until just combined.

Turn the dough onto a floured surface and roll it out to about 1/2 inch thick.

Using a donut cutter, cut out your donuts and holes.

In a frying pan or deep fryer, heat the oil to 350°F (175°C).

Carefully place the donuts in the hot oil, frying for about 2-3 minutes on each side until golden brown.

Remove the donuts and place them on a cooling rack lined with paper towels.

Dust with powdered sugar if desired, and enjoy your delicious creation!