Preheat oven to 350°F.
Slice the zucchini lengthwise into thin slices. Sprinkle them generously with salt and let them sit for about 20 minutes. This will draw out any excessive moisture. Afterwards, thoroughly pat them dry.
To prepare the red pesto: Peel the garlic and add it to a blender or food processor along with the sun-dried tomatoes, Parmesan, pine nuts, basil, and olive oil. Blend until smooth. Alternatively, an immersion blender will work. Season to taste with salt and pepper.
To make the béchamel sauce: Melt the butter in a saucepan. Whisk in the flour and cook briefly, without browning, for about 1 minute. Gradually whisk in the milk until a smooth, creamy sauce forms. Season with nutmeg, salt, pepper, and a little lemon juice.
Peel and finely dice the onion and garlic.
Then, heat 2 tablespoons of olive oil in a large skillet over medium heat. Sauté both until translucent and fragrant. Add the zucchini slices and sauté briefly until lightly browned. Season with Herbes de Provence, pepper, and, if necessary, a little salt.
Grease a 9x13 inch baking dish. Start with a thin layer of béchamel sauce, then add a layer of lasagna noodles. Now, spread some red pesto on top and then add a layer of zucchini slices, and feta cheese on top. Repeat the process until all ingredients are used. Finish with a layer of béchamel sauce.
Bake the lasagna for 30-40 minutes, or until golden brown.
Let the lasagna rest for about 5 minutes before slicing. Serve and enjoy warm!