Simmer the chicken stock with the bay leaf, cloves, lemon zest and saffron until the stock is aromatic from the zest. Remove the bay leaf, cloves and lemon zest.
Whisk together the eggs, egg yolks, and lemon juice, then whisk in the warmed stock. Return the mixture to the pot and continue whisking over low heat until the soup thickens to the desired consistency. Do not simmer or boil.
Mix in the chicken to warm, then plate, garnish with the scallion and serve.