Vegetarian Lasagna

Instructions

• 1To make the vegetables, put the sweet potatoes in a large bowl. Add 1½ tablespoons of oil and sprinkle with half the thyme. Season with salt and pepper and toss gently to coat.
• 2Insert the wire rack into the middle shelf position. Preheat the oven. Select BAKE/CONVECTION/400°F/12 minutes and press start.
• 3Line the roasting pan with parchment paper. Arrange one-third of the sweet potatoes in a single layer on the pan.
• 4Once the oven has preheated, put the sweet potatoes in the oven and bake for 10-12 minutes until tender. Transfer the sweet potato to a tray to cool and repeat twice to cook the remaining sweet potato.
• 5While the sweet potato is cooking, put the zucchini in a large bowl. Add the remaining 1½ tablespoons oil and sprinkle over the remaining thyme. Season with salt and pepper and toss gently to coat.
• 6Preheat the oven. Select BAKE/CONVECTION/400°F/12 minutes and press start.
• 7Arrange half the zucchini in a single layer on the lined pan.
• 8Once preheated, put the zucchini in the oven and bake for 10-12 minutes until tender. Transfer the zucchini to a tray to cool and repeat to cook the remaining zucchini.
• 9To make the tomato sauce, while the vegetables are cooking, heat the oil in a medium saucepan over medium heat. Add the onion and garlic and cook, stirring, for 5 minutes until soft and translucent. Add the tomato paste, cook stirring for 1 minute. Add the mushrooms, basil, garlic and thyme and cook, stirring, for 4 minutes until the mushrooms are soft.
• 10Add the tomatoes and balsamic vinegar and bring to a boil. Reduce the heat to medium-low and simmer for 5-10 minutes until the sauce has slightly thickened. Remove from the heat and season with salt and pepper.
• 11To make the béchamel sauce, melt the butter in the medium saucepan over medium heat until foaming. Add the flour and cook, whisking constantly, for 1-2 minutes until the mixture bubbles and starts to look a little grainy. Remove the pan from the heat.
• 12Add the milk slowly, whisking constantly to avoid any lumps. Return the pan to the heat, add the nutmeg and cook, stirring constantly with a wooden spoon until the sauce comes to a boil. Reduce the heat to medium-low, simmer, stirring constantly for 3 minutes until the sauce thickens slightly.
• 13Remove the pan from the heat. Add the egg and whisk until smooth. Stir in the grated Parmesan, salt and pepper.
• 14To assemble the lasagna, spread 1/2 cup (5 oz) of the tomato sauce evenly over the bottom of a 3-inch deep, 8x12-inch baking dish.
• 15Place 3-4 lasagna sheets over the sauce to cover the bottom, ensuring they don’t overlap, snapping off any excess pasta. Top with half the sweet potato and half the zucchini. Spoon over 1½ cups (15 oz) of the remaining tomato sauce. Spread 2 cups (16 fl oz) of the bechamel sauce over the tomato sauce.
• 16Top with 3-4 sheets lasagna, the remaining sweet potato and zucchini. Spread with the remaining tomato sauce then remaining bechamel. Sprinkle with parmesan and mozzarella.
• 17Cover the lasagna with a sheet of parchment paper then foil.
• 18Insert the wire rack into the middle shelf position. Preheat the oven. Select BAKE/CONVECTION/350°F/60 minutes and press start.
• 19Once preheated, put the lasagna on a large tray and bake for 30 minutes. Carefully remove the foil and parchment paper and bake a further 30 minutes until golden on top and bubbling around the edges.
• 20Allow the lasagna to stand for 15 minutes before cutting and serving.
  Tip: Before you start, check that the baking dish fits in the oven.