Boil noodles for according to package, you want them al dente.
Drain and place noodles in mixing bowl.
Preheat oven to 350F.
Melt butter in frying pan.
Add ground beef and onion, brown meat.
Add tomato sauce, simmer for 5 minutes.
Add meat sauce to noodles, mix well.
Add egg and grated cheese to pastitsio mixture, mix everything together.
Grease baking pan. Pour pastitsio mixture into pan.
*Now, let's make the Béchamel*
Heat milk in pan.
Add butter.
Stir in semolina slowly, continuously stirring
Add salt to taste.
When béchamel gets thick, remove from heat.
Spread béchamel over pastitsio.
Top with some extra feta cheese and sprinkle entire pastitsio with Cinnamon
Bake for about 45 minutes (until pastitsio top is a nice golden brown color)
Let cool before serving.
Enjoy