In a large pot, bring the 6 cups of chicken broth to a boil. This will prevent the potatoes from oxidizing.
Add the evenly sized red potato pieces to the boiling broth. Cook until the potatoes are fork-tender, which should take approximately 15-20 minutes. Test their tenderness by piercing with a fork or toothpick.
Drain the potatoes and return them to the pot. Use a potato masher or a garlic press to mash the potatoes until they are smooth and free of lumps.
Cut the unsalted butter into smaller pieces and add it to the mixture. Continue mixing until the butter is fully melted, and the potatoes have a creamy consistency.
Add the cream cheese and mix until it is well incorporated into the potatoes, making them rich and creamy.
Pour in the buttermilk and continue to mix until the desired consistency is achieved. Add it in increments if necessary.
Season your mashed potatoes with salt and pepper according to your taste. Start with a pinch or two and adjust as needed.
Serve the restaurant-style garlic mashed potatoes immediately while they are still hot. Optionally, garnish with chopped chives for a delightful finish.