Cook potatoes: Add peeled and cubed potatoes to a pot and add enough cool water to cover by at least an inch. Add a tablespoon of kosher salt and heat over medium-high until the water comes to a boil. Reduce heat slightly to establish a gentle boil (a rolling boil can rough up the potatoes too much). Cook for 15-20 minutes, or until the potatoes are easily pierced with a fork.
Sauté garlic & herbs: While the potatoes cook, heat a small saucepan over medium-low heat. Melt the butter, then add in the minced garlic, optional sprigs of fresh herbs, and fresh cracked black pepper. Keep the temperature medium-low so that the garlic cooks slowly without browning. Simmer for 5-8 minutes, till the garlic is cooked and mellow.
Heat the milk: Pour the milk into the garlic butter. Increase heat to medium and heat until the milk is just about to boil — then immediately reduce to low.
Drain and dry potatoes: Once the potatoes are fork-tender, turn off the heat and drain them into a colander. Immediately transfer them back into the hot pot. The residual heat should help some of the extra liquid cook off as steam.
Mash potatoes: Use a potato masher or ricer to mash the potatoes. (If you prefer a smoother mash, a ricer is highly recommended.) Pull out the herb stems from the scalded milk and butter mixture and discard. Add milk to the potatoes, stirring or mashing to incorporate. Optionally, fold in some vegan sour cream or unsweetened yogurt for a slight tang.
Taste and serve: Season to taste with additional salt and pepper and keep warm until ready to serve. Garnish with desired toppings: fresh chopped parsley or chives, an extra pat of butter, etc.