• Heat the oven to 425°F Place a wire rack over a baking sheet.

For the Garlic Butter:

• In a small pan set over medium-low heat, add 1 tablespoon of the butter and when it has melted add the grated garlic. Sauté the garlic for about 1 minute. Do not let it brown.
• Add the remaining butter, garlic powder, salt and pepper and cook only until the butter is melted. Remove from the heat while preparing the potatoes.

For the Potatoes:

• Scrub the potatoes to remove any soil. Pat dry with paper towels.
• Working with one potato at a time, on each side of a potato, place a small dowel, chopstick or wooden spoon handles as a guide when slicing the potatoes. Make parallel cuts at 1/4-inch wide across the potato. Cut straight down and stop when the knife hits the guide. The guide will keep the knife from cutting all the way through the potato. Repeat with each potato.
• Place the potatoes on the wire rack and brush them all over with half of the garlic butter.
• Transfer the sheet pan to the oven and bake the potatoes for 30 minutes. Remove from the oven and baste the potatoes with the remaining garlic butter. The slices will have fanned open enough to drizzle the butter down into the crevices.
• Sprinkle the potatoes generously with salt and pepper. Return the sheet pan to the oven and bake the potatoes for another 30-40 minutes, depending on their size. To test for doneness, stick a toothpick into one of center slices, if it has resistance continue to bake another 4-5 minutes.
• Transfer from the oven and serve the potatoes hot with sour cream and optional condiments. (see notes)