Filling can be made up to one day ahead. Keep, covered, in the fridge. Add 1⁄2 cup chopped fresh basil to filling for a flavour hit. Freeze leftover lasagne sheets to use later.
Cooking oil spray
2 x 375g packets fresh lasagne sheets
2 x 400g jars tomato pasta sauce
1 cup grated mozzarella
1⁄4 cup shredded parmesan
1 tblsp olive oil
1 onion, finely chopped
2 cloves garlic, crushed
1 bunch English spinach (300g), trimmed, thinly shredded
750g fresh ricotta
Spray the base and side of a 22cm springform pan (base measuring 20cm) with cooking oil. Place on an oven tray.
2 To make filling, heat oil in a large, non-stick frying pan over a medium heat. Add the onion and garlic. Cook, stirring occasionally, until soft. Add spinach. Cook, stirring until just wilted. Transfer mixture to a bowl. Cool. Add ricotta and parmesan. Season and mix well.
3 You will need 10 lasagne sheets. Reserve remaining for another use. Working with one sheet at a time, spread evenly with 1⁄2 cup spinach mixture. Starting at one short end, roll up to enclose. Using a serrated knife, cut in half crossways.
5 Spread 1 cup of the pasta sauce over base of prepared pan. Arrange lasagne rolls, cut-side up and side-by-side over base. Spoon over remaining sauce. Spread evenly. Cover tightly with a sheet of baking paper, then foil.
6 Cook in a moderate oven (180C) for 30 minutes. Remove. Increase oven to hot (200C). Discard cover from lasagne. Sprinkle with combined mozzarella and parmesan.
7 Cook in oven for a further 20 minutes, or until golden brown. Remove and stand for 15 minutes. Remove side of the pan.
8 Serve pie cut into wedges.