Preheat your oven to 180°C (160°C fan). Lightly grease a 23x33cm baking dish.

Place pistachios in a food processor and blend until finely ground, leaving some small pieces for texture. Set aside.

For the pistachio béchamel: Melt butter in a large saucepan over medium heat. Add flour and whisk continuously for 2 minutes to cook out the raw flour taste.

Gradually add warm milk while whisking constantly to prevent lumps. Continue cooking and stirring for 8-10 minutes until the sauce thickens and coats the back of a spoon.

Remove from heat and stir in ground pistachios, half the Parmesan, nutmeg, salt, and pepper. Set aside.

Heat olive oil in a large frying pan over medium heat. Sauté shallot and garlic for 2 minutes until softened.

Add asparagus pieces and cook for 3-4 minutes. Add peas and spinach, cooking until spinach wilts, about 2 minutes. Season with salt, pepper, and lemon zest.

In a small bowl, mix ricotta with a pinch of salt and pepper.

Spread a thin layer of pistachio béchamel on the bottom of the prepared baking dish. Arrange a layer of lasagna sheets on top.

Add one-third of the vegetable mixture, dollops of ricotta, and more béchamel. Repeat layers twice more, finishing with béchamel.

Sprinkle remaining Parmesan cheese evenly over the top.

Cover with foil and bake for 25 minutes. Remove foil and bake for an additional 20-25 minutes until golden and bubbling.

Let the lasagna rest for 10 minutes before slicing. Garnish with fresh basil leaves and serve.