Put 2 cups (500 ml) of water with the butter and salt to a boil in a pot. Pour the flour in at once and stir vigorously for about 6 minutes. Allow the dough to cool for 5 minutes.
Then add the eggs 1 by 1 and mix with a whisk until the dough becomes homogenized. Heat oil for frying in a pot. Take small balls of the dough and using a moistened pinky, drill small holes in the middle.
Put the Turkish donuts to fry until browned on both sides. As soon as you take them out, drop them in the cold syrup.
Boil the syrup from the last 4 products on the list and leave it to cool. Serve the donuts cold.