Combine the potatoes and 1 teaspoon of the sea salt in a 4-quart saucepan. Add just enough cold water to cover the potatoes, cover and bring to a boil over high heat, about 15 minutes. Remove the lid, drop the heat to a simmer, and cook until the potatoes are soft about another 15 minutes
Meanwhile, melt the butter in a large, high-sided saute pan over medium-high heat. Cook until the butter just starts to brown.
Add the cabbage to the pan and another 1 teaspoon sea salt and all the pepper. Sauté for 7 to 10 minutes, stirring occasionally, until the cabbage is tender and lightly browned. Remove from heat and add the whiskey, scraping the brown bits from the bottom of the pan. Set aside.
Drain the potatoes and return them to the hot pot. Shake for 30 seconds so the excess water can evaporate.
Sprinkle potatoes with the remaining 1 teaspoon sea salt. Add the cabbage/whiskey mixture and the half and half then mash the potatoes to desired consistency. Taste and season with additional salt and pepper, if desired.