1. Prepare the Crust:

1. Preheat the oven to 400°F (200°C). Line a baking sheet with parchment paper.
2. In a skillet, heat olive oil over medium heat. Add garlic and sauté for 1 minute until fragrant. Add spinach and cook until wilted, about 3-4 minutes. Remove from heat and let cool.
3. In a bowl, combine the cooled spinach, feta, ricotta, Parmesan, oregano, pepper, and salt. Mix until well combined.
4. Roll out one sheet of puff pastry on a lightly floured surface into a 10×12 inch rectangle. Spread the spinach and cheese mixture evenly over the pastry, leaving a 1/2-inch border around the edges.
5. Starting from one long side, tightly roll the pastry into a log. Using a sharp knife, slice the log in half lengthwise, exposing the spiral layers.
6. Twist the two halves together gently to form a spiral shape, then coil it into a round spiral on the prepared baking sheet. Brush the top with beaten egg and sprinkle with sesame seeds if desired.
7. Bake for 25-30 minutes, or until the pastry is puffed and golden brown. Let cool for 5 minutes before slicing and serving.