Remove chicken thighs from the refrigerator 20-30 minutes before cooking and then pat dry. Season on both sides with salt and Italian seasoning. You can use chicken thighs or breasts but I find that thighs have more flavour so I prefer to use those.
Chop up the celery, shallot, and garlic. Chop carrots. Slice lemon in half.
In a pot over medium heat, add some olive oil and then place two lemon halves, flat side down, in the pot to caramelize. Careful not to let these burn, we just want a nice and golden colour to them. This should take about 2-3 minutes. Remove and set to the side.
In the same pot, brown the chicken thighs for 1-2 minutes on each side and then set to the side.
Add in more butter if needed, then in goes the chopped celery, shallots and garlic. Stir and sauté for 2-3 minutes. Add in flour and stir for another 2 minutes.
Deglaze with white wine and stir for a minute and then add broth and water. Bring this to a boil and then simmer on low, adding the chicken back in along with a rosemary sprig for 15 minutes, partially covered.
Remove the chicken thighs and roughly chop on a cutting board. Strain the soup and then pour the broth back into the pot.
Bring to a slight bubble over medium heat and then add in the pearl couscous and chopped carrots. Cook until tender (usually about 8 minutes) and then add in the chopped chicken.
Finish by squeezing the caramelized lemon halves into the soup and adjust the seasoning to your liking (salt & pepper). Garnish with fresh Italian parsley.