Put the potatoes, whole, in a pot and cover with cold water. Salt the water. Bring to a boil, and simmer
until very tender, about 30 minutes, depending on size.
Meanwhile, drop the garlic, bay leaf
, and thyme
in a saucepan
with the milk, bring to a boil, turn off the heat, cover, and set aside to infuse 10 minutes. Pull out the garlic and herbs
, and discard.
When the potatoes
are done, drain
them and peel
while hot. Put them through a food mill
set on the smallest setting over a large pot. Beat in the butter a piece at a time. Bring the milk
to a boil and beat it in, splash by splash, until completely absorbed. You are looking for a very soft, fine puree, not unlike baby food! Check the seasonings, and serve.