To make the Tomato and basil sauce, place the olive oil in a heavy-based stockpot over medium heat. Add the onion and garlic. Cook until the onion is soft. Add the Italian passata and bring to the boil, then add the basil, sugar and a pinch of salt. Reduce the heat to low and simmer for approximately 45 minutes or until the sauce has reduced to your required consistency, stirring occasionally so that the sauce does not stick to the pot and burn, then remove from the heat. Discard garlic clove. Set aside to cool.
Preheat the oven to 200°C conventional oven/ 180°C fan-forced (400° Fahrenheit/Gas 6). Grease a baking dish (approximately 20 X 32cm in size) with butter or margarine.
To make the Besciamella sauce, melt the butter in a medium-sized saucepan over medium heat until foaming. Add the flour and stir with a wooden spoon to form a smooth paste (a roux). Allow the flour and butter mixture to cook for a minute (but do not allow it to brown). Remove from the heat. Slowly pour the cold milk into the roux, whisking constantly, until the mixture is smooth. Add the bay leaf and return to medium heat. Cook, whisking until smooth. Once smooth, continue to stir with the wooden spoon until the Besciamella comes to the boil and thickens (approximately 10 minutes). Remove from heat. Season with salt to taste and stir in freshly grated nutmeg. Set aside to cool slightly.
Meanwhile, use a sharp knife to slice the zucchini (courgette) into 5mm thick ribbons, leaving the skin on. Heat the sesame oil in a large frying pan over medium heat. Fry the eggplant slices, in batches until golden brown (approximately 2 to 3 minutes on each side). Season the zucchini with salt as you cook them and transfer to a plate lined with paper towel. Add more sesame oil and repeat with the remaining zucchini.
To assemble the lasagne, remove the lasagne sheets from the packet.
Note: If you are making your own pasta for this recipe, use 1 quantity of Fresh egg pasta and divide the dough into 2 or 3 pieces. Use a pasta machine to roll out the dough, starting with the highest setting. Fold the pasta sheet in half, then roll out through the pasta machine several times to laminate the pasta. Adjust the setting on the pasta machine and fold the pasta sheet in half each time you feed the pasta dough into the machine until the dough is very thin (approximately 1-2mm).
Ladle a thin layer of Besciamella sauce to just cover the base of the baking dish. Cover with a layer of pasta sheets that overlap slightly. Spoon Besciamella sauce where the pasta overlaps. Ladle 1/2 of the Tomato and basil sauce over the pasta sheets and use the back of a spoon to level it. Spread a little less than 1/3 of the Besciamella sauce over the Tomato and basil sauce. Layer 1/3 of the zucchini slices, overlapping slightly to cover the sauce layer. Scatter half of the thyme leaves and 1/3 of the Parmigiano Reggiano (or Grana Padano) over the zucchini. Sprinkle 1/2 of the mozzarella cheese over the Parmigiano layer. Cover with a second layer of pasta sheets, overlapping slightly. Once again spoon Besciamella where the pasta overlaps. Ladle the remaining Tomato and basil sauce over the pasta sheets and use the back of a spoon to level it. Spread a little less than 1/2 of the remaining Besciamella sauce over the Tomato and basil sauce. Arrange half of the remaining zucchini in a single layer. Sprinkle the remaining thyme leaves and 1/2 of the remaining Parmigiano cheese. Continue layering using the remaining mozzarella, final pasta layer, remaining Besciamella and remaining zucchini. Finish with a sprinkling of Parmigiano Reggiano to cover the lasagne.
Bake in a preheated oven for 25 minutes. Remove from the oven. To confirm that the lasagna is cooked, insert a knife in the center of the baking dish and hold it there for a few seconds – if the knife blade is hot, the lasagna is ready. Leave to rest for a minimum of 10 minutes before serving.
Tip: The longer the resting time, the better the lasagna will be. To take your lasagna from good to great, rest it for a few hours and reheat the portion to serve. You’ll want to have leftovers as this recipe tastes even better the day after cooking!
Cut the Zucchini lasagna into 6 portions and serve – buon appetito.