Into a medium-size pot, add cubed potatoes, 1 tablespoon Old Bay seasoning, and minced garlic. Cover with 1 inch of water.
Bring to a boil then reduce heat and simmer about 15 minutes, until fork-tender. Reserve 1/2 cup of the cooking liquid. Drain potatoes and return to the pot.
Add remaining 1 teaspoon Old Bay seasoning, vegan sour cream, vegan butter, sea salt, and ground black pepper.
Mash to desired consistency, gradually adding reserved cooking liquid as needed.
Adjust seasoning to taste. Serve hot.