Pat the chicken breasts dry with paper towels and season both sides generously with salt and pepper.

In a small bowl, mix together the minced garlic, chopped parsley, and thyme leaves. Rub this mixture all over the chicken breasts and let them rest for about 10 minutes.

Heat olive oil in a large skillet over medium-high heat until shimmering. Add the chicken breasts and sear for 5-6 minutes without moving.

Flip the chicken and cook for an additional 5-6 minutes. Add butter to the pan and baste with the melted butter and pan juices until the chicken reaches an internal temperature of 75 degrees Celsius.

Transfer the chicken to a plate and cover with foil to keep warm.

In the same skillet, add brown sugar and balsamic vinegar, stirring continuously until the sugar dissolves.

Pour in the chicken broth, scraping any browned bits from the pan. Bring to a simmer and cook for 5-7 minutes until the sauce reduces by half.

Place chopped russet potatoes in a large pot, cover with cold salted water, and bring to a boil. Then reduce to a simmer for 15-20 minutes until tender.

Drain and return potatoes to the pot. Add butter and heavy cream, then mash until smooth. Season with salt and pepper.

Spoon mashed potatoes onto plates, top with chicken, and drizzle with the pan sauce. Garnish with fresh herbs if desired. Serve immediately.