Pat chicken thighs dry with paper towels and season both sides generously with salt and pepper. This moisture removal ensures proper browning and develops delicious golden crust. Heat olive oil in a large skillet over medium-high heat until shimmering, then carefully place thighs skin-side down for 5-6 minutes until deeply golden.

Flip chicken and sear the other side for 3-4 minutes, then transfer to a clean plate temporarily. The goal is golden exterior on both sides, not cooking through completely since they'll finish cooking with vegetables.

Reduce heat to medium and add minced garlic and sliced onion to the same skillet. Stir constantly for 2 minutes until fragrant and softened, scraping up flavorful browned bits from the bottom.

Pour in chicken broth, fresh lemon juice, and lemon zest, then sprinkle thyme and rosemary throughout. Return chicken thighs to the skillet along with halved potatoes and baby carrots, arranging everything in a single layer. Bring to a simmer, cover, and cook for 20 minutes until vegetables are nearly tender and hearty savory lemon chicken thighs are cooked through completely.

Meanwhile, whisk together butter and cornstarch in a small bowl until smooth, creating a slurry. After simmering completes, remove the cover and stir the butter mixture directly into the simmering liquid. Cook uncovered for 2-3 minutes until sauce thickens beautifully and coats a spoon.

Taste the pan sauce and adjust seasoning with additional salt and pepper as needed. The citrus should balance the savory elements without overpowering them.

Garnish finished chicken with fresh chopped parsley and serve immediately while everything remains hot. Squeeze extra lemon wedges at the table for those who desire additional brightness.