Beat the eggs, then combine them in a medium-size bowl (with a flat bottom) with the lime zest, brandy, and milk.
In another bowl, mix the dry ingredients: flour, sugar, and salt.
Gradually add the flour mix to the egg-milk mixture, beating with a whisk until you have a very uniform and smooth batter. The texture should resemble that of a very light, creamy dressing.
Heat the oil in a large skillet over medium-low heat. The temperature has to be around 365 ºF degrees. Add a layer of paper towels on a baking sheet to absorb the excess oil from the finished rosettes. You will also need another flat tray or plate covered with a folded paper towel, which you will use to absorb the oil from the iron rosette mold.
To make the buñuelos, place the rosette iron in the hot oil for about a minute to heat it up. Once it’s heated, lift it up from the oil and shake off any excess oil, then place it on the tray/plate with the paper towels to absorb the oil. You don’t want the mold to be coated with a lot of oil, otherwise, the batter will not adhere to it.
After you’ve blotted the iron mold, dip it into the batter. Do not let the batter run over the top of the molded tip; submersing it about three-quarters of the way in is just fine. You will hear a searing sound as the heat of the iron tip starts cooking the batter it has touched. Immediately lift the iron rosette out of the batter bowl and dip it into the hot oil. Try to transfer the mold from the batter bowl to the pan as quickly as possible, since the still-raw batter will eventually fall off the mold.
Place the iron mold in the hot oil to fry the batter. Keep the mold in the oil for about a minute. The batter will start getting more rigid as it cooks, and you will eventually be able to lift up the mold and the buñuelo will slip off and stay in the oil (if it doesn’t easily release itself from the mold, separate it with the help of a fork or a toothpick). Once you’ve removed the mold from the oil, flip the rosette over to keep cooking on the other side. You want it to acquire a golden color all over. The time is just a guideline, you will know is ready when you see the change in color.
Fry each rosette for about 1-2 minutes per side or until golden brown. Once removed, place them on the baking sheet lined with paper towel to absorb any excess oil. Place them with the hollow side down, to avoid any pooling of the oil. Repeat the cooking process with the remaining batter. While you fry each buñuelo, you can place the iron mold back into the hot oil to warm it up, so that it’s ready to be dipped into the batter again (don’t forget to dry it before putting it in the batter!).
While the cooked buñuelos sitting on the lined baking sheet, fill a small plate with sugar (mix the cinnamon into the sugar, if using). Then, one by one, dip the buñuelos into the sugar so that the top part of them is coated with sugar (since the buñuelos will still be warm, the heat will help the sugar adhere to their surface). After this, your Buñuelos de Viento are ready to be eaten. Serve them on a large plate and enjoy!