olive oil • Bone-in chicken thighs, trimmed of the excess visible fat with skin kept intact • Kosher salt • Freshly ground black pepper • Unbleached, all-purpose flour • Large onions, peeled haved and sliced • Garlic cloves, roughly chopped • Fresh rosemary sprigs • Fresh lemon juice • Chicken broth, low sodium • Lemon zest from about 3 medium lemons • Lemon, thinly sliced chopped rosemary for garnish