Roasted Vegetable Lasagna

Method

1. 1

   Step 1

   Heat the oven to 400°F (200°C / Gas 6), with racks in the upper and lower thirds. Line two large, rimmed baking sheets, approximately 13 × 18 inches (33 × 46 cm), with baking parchment and lightly grease a deep 9 × 13-inch (23 × 33 cm) baking dish with a little of the measured oil.

2. 2

   Step 2

   Divide the zucchini / courgettes, peppers and eggplant / aubergine between the baking sheets. Toss with the remaining oil, ½ tsp salt and ¼ tsp pepper, then spread into a single layer. Roast for 25–30 minutes, turning the vegetables and swapping the trays halfway through, until tender and browned at the edges.

3. 3

   Step 3

   Meanwhile, combine the tomato passata, garlic and oregano in a medium saucepan. Bring to a gentle simmer over medium heat, then cook over low heat for 8–10 minutes, stirring occasionally, until slightly thickened but still easily pourable. Taste and add salt if needed.

4. 4

   Step 4

   Place the spinach in a large skillet / frying pan over medium heat with 1 tbsp water. Cook for 2–3 minutes, stirring, until just wilted, then transfer to a sieve and allow to cool briefly. Press out excess liquid and roughly chop.

5. 5

   Step 5

   Melt the butter in a medium saucepan over medium-low heat, then stir in the flour and cook for 2 minutes without browning. Gradually whisk in the milk, adding a small splash at a time initially to keep the mixture smooth. Bring to a gentle simmer and cook for 5–7 minutes, whisking frequently, until the béchamel lightly coats the back of a spoon; stir in the nutmeg and remaining measured salt and pepper.

6. 6

   Step 6

   Remove the roasted vegetables and reduce the oven temperature to 375°F (190°C / Gas 5), moving a rack to the center. Spread ½ cup of the tomato sauce across the base of the prepared baking dish. Set aside 1 cup of béchamel for the topping, then divide the remaining béchamel, tomato sauce, roasted vegetables and spinach into three roughly equal portions.

7. 7

   Step 7

   Cover the sauce in the dish with four lasagna sheets, breaking them to fit without substantial overlap. Add one portion each of tomato sauce, roasted vegetables, spinach and béchamel, spreading the sauces to the edges to moisten the pasta. Repeat twice more, then spread the reserved béchamel over the top and scatter with the mozzarella.

8. 8

   Step 8

   Cover the dish tightly with foil, tenting it slightly so it does not touch the cheese. Bake on the center rack for 25 minutes, then remove the foil and bake for another 15–20 minutes, until bubbling around the edges and golden on top.

9. 9

   Step 9

   Insert a small knife into the center: the pasta should be completely tender with no firm or chalky resistance. The center should reach at least 165°F (74°C) on an instant-read thermometer; if the pasta needs longer, cover again and bake for another 5–10 minutes.

10. 10

    Step 10

    Let the lasagna rest for 15 minutes before cutting so the layers settle and hold together. Divide into 8 portions and serve warm, spooning any sauce from the dish over each serving.