To dissolve the yeast, heat milk first on a saucepan until warm, then take the milk out of the heat. Add the sugar and yeast to the milk and place it in a warm place for 10 to 15 minutes.
Place the all-purpose flour and salt into a large bowl. Going back to the yeast mixture, add a tablespoon of lukewarm water and vegetable oil to it.
Make a well to the dry ingredients, then pour the yeast mixture at the centre of the well you created. Start kneading the dough until all ingredients are mixed together.
While you knead the dough, add a tablespoon of lukewarm water from time to time until it becomes a soft blistered dough.
Shape the dough into a round, place it on a bowl, and cover it with plastic wrap or a kitchen towel. Store it in a warm place for 30 to 60 minutes to let the dough rise.
When the dough is ready, transfer it to a lightly floured working surface with slightly oiled hands to shape the langos. Divide into four equal slices.
Form the slices into circles about 7-inches in diameter with edges slightly thicker than the centre. Let the pieces rest and cover them with a kitchen towel for 20 more minutes.
Heat the oil in a low-bottomed pot. Once the oil is hot, fry the langos one at a time.
Fry each side for a minute or until golden in colour. Once done, take it out of the pot, let them drain on paper towels, then serve with any topping of your choice.