In a medium bowl, mix flour, baking powder and salt. Set aside.
In another bowl, beat sugar, melted butter, milk, egg and vanilla until combined.
Next, add your dry mixture to the wet and stir to combine. The mixture will be sticky but uniform. Cover with plastic and place in the fridge for at least an hour.
Once your doughnut batter has chilled. Place in onto a lightly floured surface. Form a circle and roll it out until its 1/2 inch thick.
Using your largest cutter first, cut out 10 doughnuts. Then make your doughnut holes with the small cutter. You may have to roll the dough again to get 10.
Add the oil to the skillet and heat it up to about 360°-370°
Once your oil is hot enough, fry the doughnuts for about 1.5 minutes on each side. Be sure to fry them in batches so they all cook evenly and the pan is not too crowded. I fry the doughnut holes last (optional.) Once they're done, place them on a wire rack to drain any excess oil. Dip the doughnuts in the glaze while they are still warm and dust them with cocoa powder. Let them cool for about 15 minutes so the glaze can set. Enjoy!