To make the roasted garlic, preheat the oven to 400˚F. Place the garlic in the center of a square of tin foil, then drizzle with olive oil and season with salt and pepper. Wrap the garlic tightly in the foil, then place it in the oven and roast for 45–60 minutes, or until the exposed cloves are golden brown and tender. Set aside to cool.
To make the garlic infused cream, combine garlic, cream, butter, and thyme in a small saucepan. Place over medium heat and cook just until the butter melts. Remove from the heat, cover, and let sit for 30 minutes.
Place the potatoes in a large pot and cover with 1 inch of cold water. Add 2 teaspoons salt, place over medium-high heat, and bring to a boil. Once the potatoes reach a boil, cook for 7–9 minutes, or until tender. Drain, then transfer to a stand mixer fitted with the paddle attachment.
Strain and discard the solids from the garlic cream. Squeeze all of the roasted garlic flesh from the head of roasted garlic. Add the roasted garlic to the potatoes, season with the remaining salt, and mix at low speed. Slowly stream in the garlic infused cream. Mix just until the cream incorporates and most of the potatoes break down.
Transfer to a serving bowl and garnish with chives and black pepper.