Whisk the sugar, yeast, and milk in a large bowl, let it rest for 5 minutes.
Add the flour, egg, butter, and salt, knead for 5 minutes into a ball that sticks well.
Dust your work surface with flour, knead for 5 minutes by hand or in a food processor.
Let it rest for 30 to 60 minutes under a kitchen towel, until your dough is soft and risen.
Knead briefly, roll up, and divide into 12 equal portions.
Roll long and thin sausages from each piece of dough.
Make a circle by rolling the dough into braids, pressing the ends together.
If your dough is too soft, put it in the fridge for a while to firm up.
Let it rest again for 30 minutes.
Heat vegetable oil to 175°C.
Carefully place the donuts in the oil and fry them for 2 to 3 minutes until golden brown on each side.
Immediately coat them in the sugar-cinnamon mixture while they are still warm.
Serve and enjoy!