Beat the eggs and sugar together for a couple of minutes. Add the lemon rind, softened butter and baking powder and beat until the butter is combined. Add the flour and mix well. Cover the dough and refrigerate overnight.
Preheat the oven to 350°F.
Remove the dough from the refrigerator. Using a spoon, scoop walnut-sized pieces of dough. Roll the dough into 1/2 inches thick, 6-inch ropes. Press the ends firmly together, forming a ring. Stretch the rings slightly to open the centre of hole. (These can also be made into twists by folding the length of the rolled dough in half, then twisting a few times).
Place cookies on an ungreased baking sheet, 1-1/2 inches apart. Reduce oven temperature to 300 F, and bake the rings for 20 minutes, or until they have colour.
Once all of the cookies have been baked, place the baked cookies on a large baking sheet, piling up the cookies if necessary. Reduce the oven to 150 F and return the cookies to the oven for approximately 30 minutes or until crispy and golden in colour.