In a soup pot bring chicken broth to a boil and simmer until it reduces to 8 cups and becomes concentrated. This will take about 15 minutes. Meanwhile, in a small skillet, melt butter and when it starts to foam whisk in the flour making a roux. Whisk into reduced stock and simmer until the mixture coats the back of a spoon. Season with salt & pepper to taste. In a small mixing bowl, whisk together the lemon juice, egg yolks and cinnamon. Ladle a cup of the hot chicken soup into the yolk mixture, whisking vigorously. Repeat with another cup of hot soup. Add egg-lemon mixture to the pot, still whisking. Simmer until thickened. Should coat a spoon but shouldn't be thick like gravy. Stir in cooked Grano and sprinkle with more cinnamon to serve