Greek pastitsio. Pasta bake. My grandmother’s recipe

Pastitsio – with layers of pasta, a rich cinnamon, meat sause topped with a thicklayer of cheese sauce. This is Greece’s answer to Italian Lasagna. Let’s go to do it!
This recipe is a little diferent from the traditional one. That’s exactly how my grandmother made it.
1kg ground beef
2 large onions
4 cloves of garlic
4 tsp of olive oil
2 tsp of tomato paste
3 tomato
1 sweet pepper
for Bechamel
100 gr butter
100 gr of wheat flour
1,5 lt milk
5 eggs
salt
pepper
nutmeg
Pasta
500 g pastitsio pasta or bucatini
300 g hard cheese, kefakotyri
50 g Parmesan
Bake at 190°C until top is golden brown and set, about 40-50 minutes. Reduce heat to 170 °C at halfway mark if browning too much. let stand about 45 minutes before serving