Getting a little creative with leftovers Greek Mac & Cheese

I had cheese mixture leftover from making buregs yesterday, so I decided baked spinach with the cheese, only, after the spinach cooked, there was a lot more cheese. So I added chopped mushrooms, but turns out, didn't have enough mushrooms either, so I added some pasta shells and voila, Greek Mac & Cheese was created. It's like spanakopita, without the sweat and tears of dealing with filo, which I avoid at almost all costs.

1 onion 
1 bunch baby spinach
1 egg 
1 cup shredded akawi cheese (or jack or mozzarella)
1/2 cup feta 
1 tsp dried mint
1 pkg crimini mushrooms, chopped 
1/2 pkg pasta shells 

Saute onions til golden
 Add spinach
Cook til soft. 

Make cheese mixture with cheeses, egg, and mint 
Boil pasta til al dente, around 8 minutes 
Mix with spinach, cheese mixture and mushrooms. 
Place in a greased oven proof dish, top with Parmesan 

Bake at 350  for around 30 minutes until slightly golden.