Heat olive oil over medium-high heat in a Dutch oven or deep saute pan. Brown the lamb and beef. Remove the meat from the pan with a slotted spoon. Add the onions to the pan and saute until the onions are tinged brown at the edges - about 5 minutes. Add the chopped carrots and cook for 5 minutes. Add the mushrooms, tomato puree, thyme, parsley and cinnamon. Stir and saute for 2 minutes. Next, stir in the flour, which will soak up the juice, then stir in the wine and the beef stock. Taste and add salt and pepper, as needed. Return the meat to the pan and bring to a boil. Cover, turn down the heat to low and simmer for about 30 minutes until the lamb is fully cooked.
Peel the potatoes, cut them into large even-sized pieces and place into a pot of cold, salted water. Bring the water to a boil and cook potatoes until they are tender, about 10 minutes. (Potatoes are done when a knife can easily go through.)
When the potatoes are done, drain off the water, return them to the saucepan, cover with a clean tea cloth to absorb the steam and leave them for about 5 minutes. Next, add the butter and mash them to a puree. Season with salt and pepper. When the meat is ready, spoon it into a 9-by-13-inch baking dish and level it out with the back of the spoon. After that, spread the mashed potato evenly all over. Sprinkle the scallions on top of the potato, scatter the cheese over the scallions and bake the pie until the top is crusty and golden, about 25 minutes.