In a large skillet, add a bit of oil and cook the onions for several minutes until softened (or longer and slower for a bit of caramelization) and then toss in the garlic and cook for a couple of minutes more.  Add in all of the spinach, stirring to break it up and gently cook it until almost no moisture is visible.  Allow this to cool for a bit while you get everything else ready.

Preheat the oven to 325, get out an 11 x 17 casserole and set it on the counter on top of a large piece of parchment (saves on clean up time!).  In a large bowl (or even in the skillet, if the mix has cooled enough), stir together the onion and spinach mix, parsley, ricotta, feta, eggs, dill and pepper and set aside.

Brush your entire casserole with olive oil, line it with a piece of phyllo and then brush the entire piece of phyllo with a light layer of oil – continue with this until you’ve layered about 8 pieces of phyllo (I did 8 to 10, I lost count).  If it gets bunched up on the edges or in the corners, don’t worry about it, the phyllo will get mushed down and no one will notice.

Evenly spoon and spread on all of the filling, then line with phyllo and oil for another 8 to 10 layers.  Tuck everything in and make it tidy, then carefully cut the entire pan into pieces – you don’t need to cut all the way through, but you will sure thank yourself when it comes time to serve it up!  Brush a bit more oil between the cuts you’ve made and then bake for about an hour and a half until the top is a beautiful brown.

Allow the spanakopita to rest for about 15 minutes before cutting it (again) into slices and serving it – this is also brilliant at room temperature.