Bring a large pot of water to a boil. Once boiling, add in the potatoes and cook until fork tender (should slip off when poked with a fork).
While the potatoes are boiling, preheat oven to 425° and prepare the seasoning mixture, mixing together the butter and seasonings.
Once the potatoes are done cooking, transfer them to a baking sheet, spacing them to have enough distance between each other when smashed.
Using a potato masher, mash each of the potatoes. Using a brush, season each of them with the butter mixture. Place them in the oven for 20 minutes.
For the last 5 minutes, increase the oven temperature to 525° and broil.
Once finished cooking, let them cool for a few minutes and enjoy immediately!