Dissolve sugar in lukewarm water in a large bowl and sprinkle yeast over the top. Let yeast activate until it forms a creamy layer on top of the water, about 10 minutes.

Rinse raisins and pat dry with paper towels. Stir raisins into yeast mixture; beat eggs, lukewarm milk, and salt into yeast mixture. Beat flour into liquid ingredients until dough is smooth. If dough is too sticky, beat in 1/4 cup more flour. Cover dough and set aside in a warm place to rise until doubled, about 1 hour.

Heat vegetable oil to 375 degrees F (190 degrees C) in a large saucepan or deep fat fryer.

Scoop up dough by tablespoon and drop, a few at a time, into the hot oil. Fry until lightly browned; drain on wire racks set over paper towels. Dust with confectioners’ sugar.