Bourekas are savory filled pastries that Israelis often make with puff pastry. To lighten the recipe, this version calls for phyllo dough brushed with olive oil.
1. Rinse and drain spinach and, with water still clinging to leaves, transfer to large skillet. Cover, and cook over medium-high heat 4 to 5 minutes, or until wilted. Cool, squeeze out liquid, and coarsely chop. (You should have 1 1/3 cups.)
2. Heat 1 1/2 tsp. oil in skillet over medium-low heat. Add onion, and cook 5 minutes. Add spinach; cook 2 minutes more. Transfer to bowl, and cool.
3. Stir ricotta and feta cheeses into spinach mixture. Stir in egg. Season with salt and pepper, if desired.
4. Preheat oven to 350˚F, and coat 2 baking sheets with cooking spray.
5. Lay 1 phyllo sheet on work surface with long side closest to you; brush phyllo with oil. Top with second phyllo sheet, and brush with oil. Cut phyllo sheets lengthwise into 4 long strips. Place 1 1/2 tsp. spinach mixture on bottom of first phyllo strip. Fold one bottom corner of strip over filling to make a triangle. Continue folding phyllo strip over filling (like a flag) until filling is encased in phyllo. Brush top with oil, and transfer to prepared baking sheet. Repeat with remaining phyllo, oil, and filling; sprinkle bourekas with sesame seeds.
6. Bake 15 to 18 minutes, or until triangles are crispy and golden-brown. Cool 5 minutes before serving.