Spinach & ricotta slice - Master recipes

Ingredients

• 50g butter -
• 1 tsp olive oil -
• 1 onion , finely chopped -
• 1kg spinach -
• ¼ tsp ground nutmeg -
• 500g ricotta -
• 2 egg yolks -
• 85g parmesan (or vegetarian alternative), finely grated -
• 2 x 375g packs all-butter puff pastry -
• a little flour , for dusting -
• 1 egg , beaten -