Fill a large pot with water and add the potato chunks.
Bring to a boil over medium-high heat and cook for 15-20 minutes, or until the potatoes are fork-tender.
Drain and set aside.
For roasted garlic: Wrap unpeeled garlic cloves in foil with a drizzle of olive oil and roast at 400°F (200°C) for 30 minutes, until soft and golden.
For sautéed garlic: Melt one tablespoon of butter in a pan over medium heat, add minced garlic, and sauté for 1-2 minutes, until fragrant but not browned.
Place the drained potatoes back into the pot or a large mixing bowl.
Add butter, heavy cream, sour cream (if using), roasted or sautéed garlic, salt, and black pepper.
Use a potato masher for a rustic texture or an electric hand mixer for ultra-smooth mashed potatoes.
Adjust seasoning to taste, adding more salt or butter if needed.
Transfer to a serving bowl, drizzle with extra melted butter, and sprinkle with fresh parsley or grated Parmesan cheese.
Serve warm and enjoy.