Trim the lamb leg of excess fat and cut into 1 ½ inch cubes. Place in a medium sized bowl.
Combine 1 teaspoon salt, ground cinnamon, and ground pepper and coat the lamb evenly with the spice mixture (Optional step: Let marinate for 30 minutes).
Preheat a 6 quart pot or dutch oven over medium-high heat. Add olive oil and butter and let the butter melt. Add lamb cubes to the hot oil and let sear undisturbed for 2 minutes per side. You don't want to overcrowd the pan or let the cubes touch each other, so it's best to do this in batches. Set the meat aside.
Add chopped onion and saute for five minutes, until they have become soft and translucent.
Lower the heat to medium, add the garlic, and cook for an additional minute, until fragrant.
Add the tomato paste and cook for two minutes, stirring often.
Add wine and stir well to combine with the onion mixture. Be sure to scrape the bottom of the pan. Deglazing is your friend.
Let the wine come to a boil for one minute.
Add the lamb back in with crushed tomatoes, bay leaf, a cinnamon stick, and remaining teaspoon of salt. Let come to a boil, then reduce the heat to low.
Cover and simmer for one and a half hours.
When the ragù is almost ready, prepare the pappardelle according to package directions.
Remove ragù from heat, take out the bay leaf and cinnamon stick, and use two forks to shred the lamb.
Plate your pappardelle, top with the lamb ragù, and generously top with freshly grated mizithra cheese.