Heat 1 tbsp olive oil in a 25cm/10" ovenproof skillet over medium-high heat.

Add 1 garlic clove (pressed or grated) and sauté for 10 seconds. Add 1/2 onion, finely chopped (if using) and cook until translucent and starting to turn golden.

Stir in 1 can (700g/25 oz) passata, 1/2 cup water, 1/4 tsp chilli flakes (optional), salt and pepper. Simmer for 5 minutes on medium-low.

Stir through 1 tbsp fresh basil, chopped (or 1 tsp dried basil). Scoop out 1 cup of sauce for drizzling later. Keep warm.

In a bowl, combine 500g thawed and squeezed spinach, 500g ricotta, 1 cup shredded mozzarella, 1 egg, 1/2 cup shredded parmesan, the pressed garlic, and 1/8 tsp nutmeg. Mix well.

Preheat oven to 180°C/350°F (160°C fan/325°F gas).

Spread the remaining tomato sauce in the base of the skillet.

Lay out 8-10 fresh lasagne sheets. Spread the spinach-ricotta mixture evenly over the sheets, then roll them up tightly like a Swiss roll.

Place the rolled lasagne bundles seam-side down in the skillet over the sauce. Drizzle with the reserved 1 cup of tomato sauce and 1 tbsp olive oil.

Cover skillet with foil and bake for 25 minutes. Remove foil and bake for another 10-15 minutes until golden and bubbly. Let rest for 5 minutes before serving.