Spinach & ricotta pie

INGREDIENTS

• mild olive oil spray
• 1 medium onion , finely chopped
• 2 garlic cloves , peeled and crushed
• 250g young spinach
• 1 egg
• 250g ricotta , drained (or vegetarian alternative)
• ½ tsp freshly grated nutmeg
• 100g feta cheese (or vegetarian alternative)
• 4 sheets filo pastry (each roughly 38cm x 30cm)