Add 4 inches of water to a medium saucepan, season with 4 teaspoons of the salt, and place over high heat. When boiling, add the mushrooms and cover with a metal steamer basket, if you’ve got one. If not, use a smaller pot lid — anything to keep the little buggers submerged. Return to a boil and cook until the mushrooms begin to soften — 2 minutes.
Drain the mushrooms, move to a clean towel, roll up, and squeeze to dry. Place half of the mushrooms in a pint-sized canning jar. Top with the spices along with half the garlic. Slide the bay leaves down the sides of the jar. Top with the remaining mushrooms and garlic.
Refill the saucepan with the 1/2 cup of water, the remaining 2 teaspoons of salt, the vinegar, and the sugar. Bring to a simmer over medium-high heat, stirring to dissolve the sugar and salt. Remove from the heat and pour enough of the brine into the jar to fill to the top. If you have any leftover brine after that, dump it.
Cool to room temperature, lid up, and then refrigerate for at least 3 days before enjoying for up to a month.