Place the flour in a bowl, make a hole in the center and pour the orange juice and peel and the yeast dissolved in the slightly warm milk.
Start kneading (with a whisk / spoon, not by hand as it will be a very soft dough), then also add salt and liqueur.

Once you have a thick and smooth batter, cover the bowl with cling film and let it rise for at least 2 hours in a warm place.

When the batter is well leavened, full of bubbles on the surface, pour it into a sac-à-poche and, as soon as the oil is hot, start forming the pancakes directly in the pan, one at a time, starting from the center and continuing slowly and steadily outwards in order to obtain regular spirals.

Once the spiral is finished (try to make at least 2 full concentric circles), put the sac-à-poche aside and continue cooking until you see that it is well browned under the pancake, at which point turn it gently with the help of a spatula ( of those suitable for heat) and brown the second side.
As they are ready, lift them with a slotted spoon and let them dry on paper towels, then continue with the others.

While the subsequent pancakes are cooking, pass the ready-made ones in sugar, so that they stick well.
At this point the zippulas are ready, serve them hot, warm or cold, as you prefer!