Peel and cut potatoes into a uniform size. Then add to a large pot or Dutch oven.
Cover with cool or lukewarm water. They should be entirely submerged by about 1 inch. Adding too much water is okay, it will just take longer to start boiling. However, adding enough water is important because it ensures the potatoes cook evenly and quickly.
Once water is boiling, add salt and reduce heat to medium-high so it’s still boiling but not quite as rapidly. Boil until potatoes are tender enough to slide off of a sharp knife easily when pierced — about 20-30 minutes depending on type and size of potato.
Once tender, turn off heat. Strain potatoes and return to cooking pot (again, no further heat required). This will allow any leftover water to evaporate.
Use a potato masher (or large fork) to mash the potatoes. Then add garlic, butter of choice, milk of choice, and salt and pepper to taste (starting with ½ tsp sea salt and ¼ tsp black pepper as recipe is written).
Mash until desired consistency is reached. Mash more for creamier potatoes, less for chunkier potatoes.
Taste and adjust flavor as needed, adding more salt or pepper to taste, butter for buttery flavor / fluffier consistency, or milk as needed to thin (just be sure not to add too much or your mash can become runny).
Serve hot, garnish with parsley (optional), or more butter, salt, and pepper. Store leftovers covered in the refrigerator up to 3-4 days, or in the freezer up to 1 month (though best when fresh). Reheat in the microwave or on the stovetop, adding more butter or milk of choice as needed.
*Nutrition information is a rough estimate calculated with potato skins included and without optional ingredients.