01 - Preheat oven to 400°F. Line a baking sheet with parchment paper.
02 - In a medium mixing bowl, combine ricotta, spinach, Parmesan, egg yolk, minced garlic, salt, black pepper, and optional nutmeg until the mixture is smooth and fully blended.
03 - Unroll the puff pastry sheet onto a lightly floured work surface. Slice the pastry in half to form two even rectangles.
04 - Evenly spread the ricotta-spinach filling over one pastry rectangle, leaving a 1/2-inch border clear on all edges.
05 - Place the second pastry rectangle over the filling and gently press down the edges to seal.
06 - With a sharp knife or pizza cutter, slice the layered pastry into 12 equal strips, each about 1 inch wide.
07 - Twist each pastry strip several times and arrange them spaced apart on the prepared baking sheet.
08 - Brush each twist thoroughly with the beaten egg, then sprinkle with sesame or poppy seeds if desired.
09 - Bake for 18 to 22 minutes, or until the twists are puffed and evenly golden brown.
10 - Remove from the oven and allow to cool slightly before serving warm or at room temperature.