Preheat the oven to 200°C, fan 180°C, gas 6. Melt 10g of the butter in a frying pan and fry the onion and garlic for 4-5 minutes until softened. Add the spinach and cook for a further minute. Leave to cool.
Transfer the spinach mixture to a bowl and fold in the ricotta, Greek-style cheese, pine nuts and lentils. Mix well.
Melt the remaining butter and use it to brush 4 of the pastry sheets. Layer 2 of the buttered sheets on top of each other. Repeat to create two pastry stacks, then top each stack with 1 of the remaining 2 pieces of unbuttered pastry.
Spoon the spinach mixture into the centre of both. Pick up all corners and twist together to make a parcel. Brush with any remaining melted butter and bake for 12-14 minutes until crisp and golden. Serve with the herb salad.
Cook’s tip: for an extra burst of flavour and a more decorative finish, try sprinkling the top of the pastry with sesame or poppy seeds before baking.