01 - Place Yukon Gold potatoes in a large pot and cover with cold, salted water. Bring to a boil over medium-high heat, then reduce to a simmer. Cook until fork-tender, about 15 to 18 minutes.
02 - Meanwhile, in a small saucepan over medium heat, melt the unsalted butter and add peeled garlic cloves. Cook, swirling occasionally, until butter is golden brown and aromatic, and garlic is tender, about 6 to 8 minutes. Remove from heat.
03 - Remove garlic cloves from browned butter and mash with a fork. Set both aside.
04 - Drain the potatoes thoroughly and return to the pot. Let sit over low heat for 1 to 2 minutes to allow excess moisture to evaporate.
05 - Using a potato masher or ricer, mash the potatoes until smooth. Gradually incorporate the browned butter, mashed garlic, and warm milk until creamy and well combined.
06 - Stir in chopped chives, parsley, thyme, kosher salt, and black pepper. Taste and adjust seasoning as desired.
07 - Transfer mashed potatoes to a serving dish. Garnish with additional fresh herbs and a drizzle of browned butter if preferred.