Peel and dice potatoes.
Boil potatoes in cold salted water until fork tender.
Drain potatoes and let them steam dry for a minute.
Mash potatoes with butter and warm milk until creamy but still a little chunky.
Fold in sautéed leeks.
Season with salt, pepper, and add crème fraîche or sour cream.
Cover and keep warm.
Add sliced carrots to a baking dish with olive oil, salt and pepper.
Roast carrots in the oven.
Pat chicken thighs dry and season with salt and pepper on all sides.
Place chicken skin side down in a hot pan and cook until skin is golden and crispy.
Flip chicken and cook through.
Remove chicken from pan, loosely tent with foil and set aside.
Add shallot to the same pan and cook until soft.
Add grated garlic.
Deglaze with white wine, scraping up brown bits.
Add chicken broth and let it reduce.
Finish sauce with lemon zest, juice, and cold butter until glossy and silky.
