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.