Lasagna with Pesto Green Beans and Potatoes

For the Basil Pesto

1. Prepare the pesto. You can keep it in the refrigerator for up to 3 days. Wash the basil leaves in cold water. Place them in a large bowl with plenty of ice for 3-4 minutes. This will make your pesto super green!
2. Dry the leaves VERY WELL on a kitchen towel. Place them in a food processor with the garlic, pine nuts and grated Parmigiano cheese.
3. Coarsely chop the ingredients for a few seconds. Add the salt and the grated Pecorino Fiore Sardo cheese. Mix all the ingredients together for about 1 minute.
4. Add the extra virgin olive oil. Blend for about 5 minutes until the pesto is ready, green and creamy! TIP: pesto should not get hot, so use the food processor at the lowest speed and in pulses, that is, blend for a few seconds, stop and start again.

For the Bechamel

1. Make the béchamel sauce, which you can refrigerate for up to 3 days (if you're not using it right away). Melt the butter in a saucepan over low heat and add the flour - using a sieve - whisking quickly.
2. Cook for 30 seconds/1 minute, stirring, so that the flour becomes more flavorful and absorbs the fat from the butter.
3. Meanwhile, heat the milk without bringing it to a boil.
4. Turn off the heat. Slowly pour the hot milk over the roux, stirring well with a whisk to prevent lumps from forming.
5. When the milk is completely poured over the roux sauce, return the saucepan to low heat.
6. Continue stirring until you reach a fairly thick consistency (about 10 to 15 minutes).
7. The sauce is ready when it sticks to the back of a wooden spoon. Finally, taste and add a pinch of fine salt to taste.

Make the Layers

1. Place the potatoes in a large pot of lightly salted water. Bring the water to a boil. When it boils, add the green beans and cook for 15 to 20 minutes.
2. When vegetables are cooked, drain and set aside.
3. Prepare the pesto béchamel sauce. In a bowl, add the pesto to the béchamel sauce and mix. Set aside.
4. Spread a little pesto béchamel sauce on a baking dish, then add enough lasagna to cover the bottom of the dish. Top with another layer of pesto béchamel sauce.
5. Add 2 to 3 tablespoons of Parmigiano cheese. Then add some roughly chopped potatoes and green beans, covering the entire surface.
6. Cover with another lasagna and start again: pesto sauce and béchamel sauce - parmigiano cheese - green beans and potatoes (repeat).
7. Continue making layers until all the ingredients are finished, or at least until the baking dish is full.

The Baking

1. Top with a sheet of lasagna, a layer of pesto béchamel sauce and plenty of grated Parmigiano cheese.
2. Cover the pesto lasagna with aluminum foil. Bake in a preheated oven at 180°C (356°F) for 20 minutes.
3. Remove the aluminum foil and finish cooking in the oven for an additional 10 minutes.
4. Allow the pesto, potato, and green bean lasagna to cool to room temperature for 10 minutes before serving.