In a large bowl, mix the mashed potato, yeast, sugar, and flour together until combined.
Add the oil and salt to the mixture and continue mixing with your hands or a wooden spoon until a dough forms. If necessary, add extra flour if the dough is too sticky or an additional tablespoon of milk if it’s too dry.
Knead the dough on a lightly floured surface for 5 minutes until it’s smooth and elastic. Place in an oiled bowl, cover with plastic wrap or kitchen towel and set aside for 1 hour or until doubled in size.
Divide the dough into 12 equal pieces, roll each piece into a ball and flatten with your hands. Place the flattened dough on a greased baking sheet and cover it with plastic wrap or a kitchen towel, and set aside for 30 minutes.
Heat 1 inch of oil in a large saucepan until it reaches 350°F. Fry the langos one at a time, flipping once when they’re golden brown (about 2 minutes per side). Drain them on paper towels before serving.
Rub each langos with garlic clove and sprinkle salt to taste before enjoying!