Wash and cut the potatoes leaving the skins on and put them in a pot with just enough water to cover them.
Bring the water to a boil, add about ½ tablespoon of salt and the whole garlic cloves then cook until the potatoes are fork-tender.
While the potatoes are cooking, make the brown butter.
Cut the butter into pieces then add to a skillet over medium heat. Stir the butter allowing it to melt evenly. You’ll see it start to foam ~ keep stirring constantly.
Add the chopped sage.
The foam will subside and the butter is finished when it becomes a light golden color with a nutty aroma. When it's finished, set it aside.
Drain the potatoes and discard the garlic cloves.
Reserve 2 tablespoons of brown butter and add the rest to the potatoes along with the milk and goat cheese. Mash using a potato masher.
Transfer the potatoes to a serving dish, drizzle the last tablespoon of brown butter over the top and serve right away.
NOTE: see the body of this post for instructions on how to make Brown Butter Mashed Potatoes ahead of time.