Spanaki Politiko (spinach the Istanbul way)

Why I Love This Recipe
My grandfather was Greek from Turkey. His family left Istanbul in 1921.
My great-grandmother used to do this dish but, like many Greeks, did not have a cookbook. She'd do everything "me to mati" - literally, she'd rely on her experience, sight, taste and instinct. One day my mom found this dish in a restaurant and tried figuring out the recipe on her own. She came up with this recipe which she has been doing for years.
But because I never do as I'm told and always have to tweak recipes, I added cinnamon.
Ingredients You'll Need
2 lbs whole frozen spinach, thawed
1/2 lb ground beef
1 small onion, chopped
Salt & pepper to taste
About 1 tbsp parsley, chopped
About 1 tbsp mint or basil, chopped
2 tbsp butter
the juice of half a lemon
1 tbsp soup rice (optional)
1/2 to 1 tsp ground cinnamon (optional)
Directions
Sauté the thawed spinach in a pan with 1 tbsp butter
In another pan, sauté the ground beef with the onion and herbs, and season to taste (if you want to use cinnamon, add it now); add a little bit of water and allow to simmer for 10 minutes
Add the meat and rice (if using) to the spinach, season to taste, add the lemon juice and mix well
Cover the pan and let cook for about 15 minutes
Serve with Greek-style yogurt