Slightly-Fancy Mashed Potatoes (Steeped with Garlic, Onion, and Herbs)

Clean the potatoes. Trim off any blemishes or eyes, and peel if desired. If using russets, cut the potatoes into thirds or quarters to speed boiling time.
Note: You DO have to peel russet potatoes. Gold potatoes can be eaten peeled or with the skins.
Boil the potatoes in a pot of well-salted water until fork tender. Drain the potatoes and return to the pot, letting the residual heat evaporate excess moisture.
While the potatoes boil, bring the half-and-half or milk just to a boil in a small sauce pot with the butter, onion, thyme, bay leaf, rosemary, garlic, nutmeg, and 1 1/2 teaspoons of kosher salt, stirring occasionally. (I use Diamond Crystal salt; use less if using Morton's or table salt.)
As soon as the liquid begins to boil, immediately remove the pot from the heat and let the liquid steep. Make sure not to let the mixture boil over.
Strain most of the butter and milk through a sieve into the potatoes, discarding the onion, garlic, and herbs. Add some fresh black pepper. Mash and stir until fluffy and well mixed. Add the rest of the butter and milk as necessary.
PRO TIP: I like to mash that potatoes in the pot over low heat, to keep them hot.
Taste for seasoning, adding more salt or another splash of milk if necessary. Serve hot, with a pat of butter on top, and maybe a sprig of thyme and a few twists of black pepper.