Mix the sugar and the flour together and create a well. Add the eggs and the oil and bring the flour-sugar mixture from the sides into the egg-oil mixture. Mix until you create a ball, similar to pie dough. It should be soft and elastic. Set aside and prepare the filling.
Grind the almonds and place in bowl. Add the sugar, lemon zest, the eggs and mix well.
Preheat the oven to 200C (400F).
Take 1/3 of the dough and roll into a 2cm (4/5 inch) diameter snake. Cut the snake into 5cm (2 inch) pieces and roll each one flat into a rectangle.
Put one teaspoon of almond filling in the middle of the rectangle and bring the long sides together over the filling and pinch together into a crest.
Then shape the dough into the shape of the letter "S".
Bake the biscuits at 200C (400F) for 5 minutes and then reduce the temperature to 180C (350F) for an additional 15 minutes.
Roll them immediately in icing sugar (confectioner's sugar) and let them cool.