Combine milk, eggs, sugar, vanilla and flour in a large bowl. Using a large stand mixer, beat to create a smooth thin batter. Heat the lard or oil to 400 to 425 degrees. The pan should be 3/4-full of oil. Heat the rosette iron by dipping it in the hot oil for about a minute so the batter won't stick to it. Dip the heated iron into the batter to the iron's top edge but not covering it. Then dip the batter-coated iron into the hot oil to fry, holding the iron there until the batter firms and puffs up. After about 5 seconds, the batter should shake off the iron. Fry the rosette another 5 seconds or so, until golden brown. Remove the rosette with tongs and lay on paper towel so the oil soaks off and the pastry cools. Cooling happens quickly. When cool, sprinkle confectioners' sugar on top. Between each rosette, dab the oil off the iron onto a paper towel before dipping again in batter