Season the chicken with salt and black pepper. Heat olive oil in a skillet over medium-high heat and sear the chicken for 6-7 minutes per side until golden brown. Transfer to a warm plate.

In the same skillet, reduce heat and melt butter. Add minced garlic and sauté for 1-2 minutes until fragrant.

Sprinkle flour over the garlic and stir continuously for 1-2 minutes to form a roux.

Gradually whisk in chicken broth and cook for 4-5 minutes until the mixture thickens. Add heavy cream if using, and season to taste.

Boil peeled and cubed Yukon Gold potatoes in salted water until fork-tender, about 12-15 minutes. Drain and return potatoes to the pot.

Mash the potatoes with butter, milk, and shredded cheese until creamy. Season with salt and pepper to taste.

To serve, plate the cheesy mashed potatoes, top with chicken, and drizzle with gravy. Garnish with parsley or chives.