Preheat oven to 350 degrees F.
Melt the butter in a pan. Sauté onions until translucent then add the garlic. Sauté an additional minute then remove from heat.
Add the spinach, eggs, Parmesan cheese, dill, parsley, and onion mixture to a mixing bowl.
Spray a 9x13 pan with olive oil spray. Add one sheet of phyllo dough, then spray the sheet of phyllo dough. Repeat four more times.
Add the spinach mixture and evenly spread it out.
Add a sheet of phyllo dough and spray with olive oil spray. Repeat 9 more times.
Bake in the oven 35-40 minutes.