In a large mixing bowl, combine the 00' flour, granulated sugar, dry instant yeast, and salt. In a small saucepan, melt the butter and mix with the milk until warm but not boiling. Gradually add to the dry ingredients, followed by vanilla extract and medium egg. Knead on a floured surface for about 6 minutes, until smooth and elastic.

Shape the dough into a ball and place in a greased bowl, cover, and let it rise in a warm spot for approximately 1.5 hours, or until doubled in size.

Once risen, punch down the dough gently, divide into four portions, and roll out each into a thin circle. Spread chocolate spread on the first three circles, leaving the top circle plain. Stack the circles.

Flatten the stacked dough slightly and cut into 16 strips, twisting each outward to create the star shape.

Let the twisted dough rest for 30 minutes. Preheat the oven to 180°C (350°F). Brush with beaten egg whites and bake for 12-15 minutes until golden brown.

Cool slightly on a wire rack, dust with powdered sugar if desired, and serve warm.