Peel and cut potatoes into even chunks, reserving some skins. Place in a pot, cover with cold water, and add 1 teaspoon salt. Bring to boil, reduce to simmer, and cook until fork-tender (15–20 min).
Make the brown butter infusion:
In a skillet, melt butter over medium heat. Cook until golden brown and nutty (3–5 min). Stir in garlic and rosemary for 30 sec. Remove from heat.
Mash it up:
Drain potatoes, return to pot to steam dry 1–2 min. Mash or rice, then stir in warm milk and cream. Add garlic-rosemary brown butter. Mix gently, season with salt and pepper.
Level-Up Option 1:
Broiled Golden Top: Spread mashed potatoes in buttered baking dish, dot with butter, broil 3–4 min until golden.
Level-Up Option 2:
Crispy Potato Skins: Slice reserved skins thinly, pat dry. Fry in olive oil until golden, drain on paper towels, salt, then scatter on top before serving.
Video
Notes
Add Parmesan to brown butter for even more depth.
Swap rosemary for thyme for a sweeter, earthy flavor.
Can be made 1 day ahead—reheat gently with extra milk or cream.