For the dish
In a pot full of well-salted boiling water, add the pasta and boil for 2 minutes less than those mentioned in the instructions in the packaging. Drain and reserve some of the pasta water.
Preheat a deep baking pan at medium to high temperature, add the zucchini, salt and sauté, until it gets a uniform brown color from both sides. Add the onion and resume sautéing, until it gets a uniform color as well. Pour the boiled pasta in a baking pan, add some of the pasta water and stir. Lower the heat to medium, add the pesto, half of the grated OLYMPOS feta cheese, the basil leaves, some pepper and stir, until you get a thick texture. Taste, season to taste, if necessary and serve in deep plates garnishing the rest of OLYMPOS feta cheese.
For the pesto
In a chopper blender, add all the ingredients, apart from the kefalotyri cheese. Turn the blender on and beat at high speed, until you get a homogenous mixture. Add OLYMPOS kefalotyri cheese and resume beating, until it is incorporated as well. Season to taste, if necessary.