Steps
- Preheat the oven to 350°F / 180°C. Melt 25g of butter with 1 teaspoon of olive oil in a pan; soften 1 finely chopped onion over medium-low heat for 10 minutes. Transfer to a bowl.
- Wilt 1kg of spinach in batches in the pan. Drain, squeeze thoroughly dry, chop, and add to the onion with ¼ teaspoon of ground nutmeg, 500g of ricotta, 2 egg yolks, and 85g of grated Parmesan. Season with salt and pepper.
- On a floured surface, roll half of 750g of all-butter puff pastry into a 10 × 12in / 25 × 30cm rectangle. Transfer to a lined baking sheet; add the filling, leaving a 2in / 5cm border.
- Beat 1 egg and brush the border. Roll the remaining pastry slightly larger, cover, and crimp the edges. Brush with egg and lightly score the top.
- Bake for 40 minutes, until puffed and golden. Cool for 10 minutes before slicing.