In a medium bowl, whisk together the flour, granulated sugar, yeast and salt.
In a large bowl, whisk together the evaporated milk, egg and 2 tablespoons oil until smooth. Stir in 1/2 cup warm water. Set aside 1/3 cup of the flour mixture and stir half of the remaining flour mixture into the milk mixture. Gradually stir in the remaining half of the flour mixture to form a stiff dough. With floured hands, knead the dough in the bowl until its smooth but not sticky. Cover with a kitchen towel and let stand at room temperature for 10 minutes.
Line 2 large baking sheets with wax paper. Sprinkle the work surface and rolling pin with some of the reserved flour mixture. Roll out the dough into a 12-inch square. Cut into 16 squares. Transfer the squares to the prepared baking sheets, cover with a kitchen towel and let stand in a warm place for 2 hours.
Fill a large pot with enough oil to reach a depth of 2 inches. Heat over medium-high heat until it registers 360 degrees on a deep-fat thermometer. Working in batches of 3, fry the squares of dough, turning carefully with a slotted spoon, until golden-brown and puffed, about 2 minutes. Transfer the beignets to a paper-towel-lined plate to drain. Dust the beignets generously with the coffee and confectioners sugar; serve hot.