Mix ½ teaspoon sugar with warm milk and sprinkle dry yeast. Give it one last mix. Leave for 3-5 minutes for it to get foamy.
In a standing mixing bowl, add the rest of the ingredients for the donuts. Mix to incorporate and then knead for 10 minutes. Oil your hands a bit and form the dough into a ball. Place it in an oiled bowl and coat it with some oil to prevent crust forming on its surface. Cover the bowl tightly with a cling film and leave for the dough to rise double its size, in a warm and draft free place.
After doubled its size, place the dough on a working surface and lightly knead it into a log. Cut it into 10 equal pieces. Form each piece into a ball. Cover the balls loosely with cling film while not using to prevent them getting dry.
Take 1 ball and flatten it a bit. Poke a finger in the center of the ball and make the hole big enough so that you can use 2 fingers to roll and gently stretch it to make the hole even bigger. Make the hole bigger than normal as it will shrink when we fry the donut later. Set aside and continue with the rest of the balls.
Leave them for 10 minutes so that they puff up a bit. Then fry in hot oil on low medium heat until they're golden brown and fully cooked. Place them on a kitchen paper to help absorb the oil. While still warm, coat them in cinnamon sugar. Serve and enjoy!