Combine the milk and yeast and mix well. Allow to sit at room temperature for 10 minutes until bubbly.

In another bowl, mix the eggs, egg yolk, vanilla, orange zest and sugar until creamy.

Add the milk and yeast and mix well then add the butter and give it a good mix.

Stir in the flour and salt and knead for 10 minutes on a stand mixer or 20 minutes by hand.

Transfer the dough in a bowl slightly greased with oil and cover it with plastic wrap.

Allow to rise at room temperature for 1 hour.

Transfer the dough on a floured working surface and roll it into a sheet that has between 0,5 and 1cm thickness.

Cut out round shapes using a cookie cutter.

Cover the cut shapes with plastic wrap or a clean kitchen towel and allow to rise at room temperature for another hour until double in volume.

Heat 2 cups of oil in a deep saucepan over medium to high flame.

Carefully drop the cut out donuts into the hot oil, making sure that the top of each donut comes in contact with the hot oil first.

Fry the donuts briefly on each side until they become golden brown.

Remove the donuts on paper towels then while still warm, dust them with powdered sugar or roll them through granulated sugar.