Preheat the oven to 350°F. Put the potatoes in a medium oven-proof pot (with a cover) and add about 1 tablespoon of the butter, cut into pieces. Cover and bake in the oven for 20 minutes.
Take the potatoes out and mix them so they’re coated with butter. Sprinkle the potatoes with sale. Return to the oven, cover, and cook for another 45 minutes to an hour, depending on how large the potatoes are.
To test for doneness, poke a potato with a fork. If the fork penetrates easily, they’re done. When the potatoes are nice and soft, remove the pot from the oven and, using a potato masher, crush each potato. Don’t pound them into oblivion, just crush them. Toss with the garlic and remaining butter. Add more salt to taste.