Ingredients

Step by step

1. Preheat the oven to 200°C, fan 180°C, gas 6. Fully line a loose-based 20cm square cake tin with a double layer of foil and grease with a little butter. Cut 2 long strips of baking paper, 20cm wide, and lay them in the tin crossways, with the excess extending over the sides.
2. Melt 25g of the butter in your largest saucepan. Cook the leeks and garlic with a pinch of salt over a medium-low heat for 5 minutes until softened. Add the spinach (in batches if necessary), cover and leave to wilt for 5 minutes. Stir to combine, season with nutmeg and black pepper and tip into a colander over a large bowl to drain.
3. Melt the remaining 100g butter in a large pan. Add the flour and cook for 1-2 minutes, stirring. Remove from the heat and gradually add the milk. Cook on a medium heat, stirring continuously, until the sauce has thickened. Turn off the heat and whisk in two-thirds of the Parmesan, followed by the ricotta, until smooth. Season to taste and spoon out 2 ladlefuls of the sauce to reserve for the top of the lasagne. Stir the drained spinach and leek mixture into the sauce left in the pan.
4. Put the lasagne sheets in a heatproof dish, cover with boiling water from the kettle and leave to soften for 1 minute then lift out to a board. Cut the sheets to size so that they will fit neatly into the prepared tin.
5. Spread a thin layer of the spinach sauce (about one-eighth) in the base of the prepared tin. Scatter with a small handful of feta, followed by a layer of lasagne sheets. Repeat these three layers, seven more times, finishing with lasagne sheets. Spread over the reserved white sauce, then scatter with the remaining Parmesan and the pine nuts.
6. Sit the tin on an oven tray; bake for 40-45 minutes until golden brown and bubbling. Rest for 15 minutes and serve, or see our Get Ahead tip above.
7. To reheat, preheat the oven to 190°C, fan 170°C, gas 5. Push the lasagne out of the tin from the base and cut into 9 squares. Place the desired number of squares in a large ovenproof dish, cover with foil and bake for 35-40 minutes until piping hot. Uncover and bake for a further 5 minutes to crisp up the top. Any other squares can be frozen for another time, then defrosted before reheating.
   
   *Use vegetarian cheese if required

Serve with

Courgette and radish ribbon salad with basil dressing

Roasted squash, olive, avocado and rocket salad

Balsamic courgette, pine nuts and Parmesan salad