In a large mixing bowl, combine the all-purpose flour and sugar. Gradually add a beaten egg and mix until a soft dough forms.

Knead the dough on a lightly floured surface for about 5 minutes until smooth and elastic.

Wrap the dough in plastic wrap and let it rest for 30 minutes at room temperature.

Roll it out to a thickness of about 1/8 inch and cut out 3-inch circles.

Heat vegetable oil to 350°F (175°C). Fry the dough circles in batches for 1 to 2 minutes until golden brown.

While the pastry shells cool, prepare the sweet ricotta filling by blending the ricotta cheese, powdered sugar, vanilla extract, and optional citrus zest.

Fill the pastry shells with the ricotta mixture using a piping bag fitted with a wide round tip.

Garnish with chocolate chips or crushed pistachios before serving.