In the bowl of a stand mixer combine the packet of yeast, sugar and warm water together. Whisk well.

Add the egg yolks, milk and vanilla extract to the yeast mixture and use dough hook or whisk to combine.

Add the flour mixed with the salt gradually on low speed, until the dough comes together and begins to form a ball. In small spoonfuls add the soft butter to the dough, mixing well between each addition. As you mix, the dough will start to pull away from the bowl and become shiny and smooth and very elastic. Knead about 5 minutes using the dough hook.

Remove from bowl and shape into a ball. Rinse out mixing bowl and coat with a teaspoon of oil. Take your dough ball and, place into bowl, turning to coat all sides. Cover well with plastic wrap and place in a warm spot to rise until doubled in size, 1.5 to 2 hours.

Line a large baking sheet with parchment paper.

On a lightly floured surface roll dough into a 1/4" thick rectangle. Use a 2.5" or 3" round biscuit or cookie cutter to cut out your dough rounds. Place on parchment lined sheet. Gather the scraps and cut as many as the recipe will allow. Cover the tray with a damp towel and place in a warm place to rise for 30 minutes or until puffy.

Pour 2" of oil into a large Dutch oven or a very large pot and place over medium heat.  Heat the oil to 350 -  365 degrees, using a deep fry thermometer.

Working in batches of four, add the dough rounds to the hot oil and fry, flipping once, so that each side is golden brown. This should take no more than two minutes total and mine took less.

Let cool slightly and then either use a straw to poke a hole in the top middle of the donut or a sharp knife to slit the side open and then squirt in your filling of choice using a pastry bag or a ziploc with one corner snipped off. Place donuts on a wire rack and sprinkle well with powdered sugar. Best served immediately.