Peel the potatoes and remove any blemishes or dark spots. Chop them into a 1 to 1 ½ inch dice.
Place the diced potatoes into a large pot with 2 teaspoons of salt. Cover with cold water by about an inch.
Bring the water to a boil over high heat, then reduce the heat to medium-low and simmer until the potatoes are easily pierced with a knife or fork, about 15 minutes.
Turn off the heat. Reserve about 1 cup of the potato cooking water before draining the potatoes.
Return the drained potatoes back to the hot pot and let them sit for 2 to 3 minutes to cook off any excess water.
Using a potato masher, mash in the the vegan butter and remaining ½ teaspoon salt until the butter is fully melted.
Add ¼ cup potato cooking water and mash until smooth and creamy.
Stir in the milk and black pepper.
Add any additional reserved cooking water or milk to reach the desired consistency. Taste and add any additional seasoning, as necessary.
Serve with an extra pat of butter, if desired, and freshly cracked black pepper.