In a pot with boiling salted water add 1 table spoon of olive oil and the bucatini, cook according to the packet instructions minus 30-45 seconds, while the pasta is cooking start the ragu. When pasta is ready drain and set aside.
Heat a large skillet. Add the oil and the pepper, lower the heat to medium-high.
Add the the garlic and give it a stir with a wooden spatula, add onions and sprinkle the salt over them , let them rest for 30 seconds, add the berbere mix everything well and keep stirring for a minute or so until the onions become from white to a semi-transparent color.
Sauté for 5 minutes, until the onions wilt and turn golden brown, all their water is gone and they are left only with the oil. (If they start sticking to the bottom of the pan add a little beer and scrape the bottom of the pan with your spatula, till most of the beer is gone.)
Add the cubed aubergine, the zucchini slices, the sliced mushrooms and saute for 5-7 minutes. When the aubergine turns from white to a semi-transparent color, add a small amount of the beer about 1/4 cup and stir. As soon as it starts bubbling lower the heat to low (⅓ of your stoves range)
Simmer for 20-30 minutes until all the liquid is gone and all that is left is the oil. Stir in the fresh parsley, the oregano and keep stirring for 30 seconds, Take it of the heat and set aside.
While your are waiting...
In a 13 x 9 x 2 inch (30 x 20 x 5 cm) lightly oiled baking pan layer the bucatini 1 inch (2.5cm) high at the most.
In a small mixing bowl beat two eggs add 1/2 cup (50g) Parmesan cheese, mix in well and pour over the bucatini while tossing so it coats all of the pasta and makes an even layer.
Preheat the oven to 180℃, 350°F, gas mark 4.
In a large mixing bowl, beat the eggs and add the yogurt, the feta, the manouri and the parmesan cheese minus 3 table spoons to use on the top later, blend thoroughly using your hand blender until it becomes smooth and creamy and set aside.
Take one cup of the the yogurt béchamel and mix it well with the ragù that's waiting, then scoop it over the bucatini and spread it to an even layer.
Pour over the yogurt béchamel and even it all out. On top sprinkle with the rest of the Parmesan cheese and the bread crumbs.
Put it in the oven and bake for 30-40 minutes until the top starts to turn golden brown. Remove from the oven and let it stand and cool of for 15-20 minutes before cutting into 12 pieces.
You can make this pastitsio from the day before, after it cools complete cover and put in the fridge. Take it out of the fridge about 1 1/2 hour before reheating.
Preheat the oven to 150℃, ??°F, gas mark 4. Heat it for about 15-20 minutes.
To preheat a pan dry, put on high until you can feel the heat on the palm of your hand holding it about 6 inches, 15cm, above the bottom.
When you add salt right over your onions, it helps shed their water quicker and they are less likely to burn.