Preheat the oven to 220 degrees C (or 200 degrees C fan-assisted). Finely chop the garlic and onion. Wash the leek and cut it into thin half-moons. Crumble the ricotta into a small bowl.

Heat a drizzle of olive oil in a sauté pan over medium-high heat. Sauté the onion, leek, and garlic for 4-6 minutes. Season with salt and pepper. Set aside 30 g of spinach per person, then add the rest to the sauté pan. Cook until the spinach wilts. Deglaze with white wine vinegar.

In a saucepan, melt the butter and whisk in the flour to make a roux. Add milk gradually, mixing until smooth, then bring to a boil. Add nutmeg, pecorino, salt, and pepper.

Brush an oven dish with olive oil. Layer with béchamel, lasagne, vegetables, and salmon. Continue layering, finishing with béchamel and remaining pecorino.

Bake for 25-40 minutes until golden brown.

Before serving, add semi-dried tomatoes and reserved spinach to salad. Mix and serve lasagne with the salad sprinkled with hazelnuts.