Heat olive oil in a sauté pan over medium heat. Add diced onion and cook 3 minutes until translucent. Add fresh spinach and stir until wilted, about 2-3 minutes. Transfer spinach to a colander and press firmly for 5 minutes to remove moisture, then chop roughly.
2 tablespoons olive oil, 1 small onion, 8 oz fresh spinach
In a mixing bowl, combine the pressed spinach, crumbled feta, ricotta, salt, and black pepper. Mix until evenly distributed but with visible feta chunks. Taste and adjust salt as needed.
8 oz fresh spinach, 4 oz feta cheese, 4 oz ricotta cheese, to taste salt, to taste black pepper
Cut cold puff pastry into 4-inch squares. Place 2 tablespoons of filling in the center of each square, leaving a ½-inch border. Fold the pastry into a triangle and press edges firmly with fork tines to seal completely. Repeat with remaining squares.
1 package puff pastry sheets
Beat egg with 1 tablespoon water. Brush egg wash on all exposed surfaces of the bourekas. Sprinkle with sesame seeds if using. Place bourekas 2 cm apart in a preheated air fryer basket at 350°F. Air fry for 10-12 minutes until golden brown and puffed.
1 large egg, optional sesame seeds
Remove bourekas to a cooling rack and let rest for 5 minutes so the filling sets and cheese stops bubbling. Serve warm for best texture.
