Preheat oven to 350F.
Cook noodles per package instructions, making sure they are al dente.
While noodles are cooking, melt butter in frying pan on medium high heat.
Next, add in ground beef and onion - cook together until meat is browned and onions are softened.
Next, add tomato sauce and simmer for five minutes. When done, turn off heat and remove from burner.
Combine meat sauce and noodles in a bowl. Add in feta cheese and 1 egg, mix well.
Pour mixture equally into a greased 6 tin muffin pan.
Set aside and make Béchamel.
Melt 2 tbsp butter in saucepan on medium heat.
Add milk, and heat until warmed through - do not allow to simmer/boil.
Slowly add semolina, mixing continuously. Add salt to taste if desired.
Once mixture gets thick, remove from heat (trick: try scooping some of the mixture up with a spoon and then drizzle it back into the pot. The mixture should fall slowly enough from the spoon but still have good movement. It should NOT get stuck to the spoon).
Pour some béchamel over the top of each pastitsio muffin.
Evenly sprinkle feta cheese and cinnamon over each piece.
Bake for 20-30 minutes, or until tip of feta becomes golden brown.
Let cool before serving.
Enjoy :)