I saw this on the Amrerican Test Kitchen and had to try it. This is my second attempt (I forgot the wrap the pan with foil the first time and it let the moisture out). They used rosemary but I used chives.
Kosher or table salt can be used in this recipe. The salt can be strained to remove solid bits and reused for this recipe. The potatoes can be prepared without the roasted garlic butter and topped with other garnishes such as sour cream, chives, crumbled bacon, and/or shredded cheese.
INGREDIENTS
2 1/2cups salt
4 russet potatoes , scrubbed and dried (I used two)
2sprigs plus 1/4 teaspoon minced fresh rosemary (I used chives)
1whole garlic , outer papery skin removed and top quarter of head cut off and discarded
4teaspoons olive oil
4tablespoons unsalted butter, softened
INSTRUCTIONS
1. Adjust oven rack to middle position and heat oven to 450 degrees. Spread 21/2 cups salt in even layer in 13 by 9-inch baking dish. Gently nestle potatoes in salt, broad side down, leaving space between potatoes. Add rosemary sprigs and garlic, cut side up, to baking dish. Cover baking dish with foil and crimp edges to tightly seal. Bake 11/4 hours; remove pan from oven. Increase oven temperature to 500 degrees.
2. Carefully remove foil from baking dish. Remove garlic and set aside to cool. Brush exposed portion of each potato with 1 teaspoon oil. Return uncovered baking dish to oven and bake until potatoes are tender when pierced with tip of paring knife and skins are glossy, 15 to 20 minutes.
3. Meanwhile, once garlic is cool enough to handle, squeeze root end until cloves slip out of their skins. Using fork, mash garlic, butter, 1/8 teaspoon kosher salt (or pinch table salt) and minced rosemary to smooth paste. Remove any clumped salt from potatoes (holding with kitchen towel if necessary), split lengthwise, top with portion of butter, and serve immediately.
This is the setup photo. I'll add the results upon completion. I had to crack open the top to get the temp up to 450* (I over shot a bit). These will be served with some filets in an hour and a half or so.