These are Hasselback Potatoes.
Potatoes with a capital 'P'.
That's how good they are.
This is a recipe I have never bothered to put down on paper (or magnetic-ferrous-particles) because of the few ingredients needed. In order to make it easier to follow the haphazard instructions below I suggest you go take a look at the finished product before starting.
Potatoes(any kind, 1-2 per *normal* person)
Before anything else throw a stick of butter into the freezer. Trying to cube room-temperature butter is an exercise I wouldn't wish even on my enemies. No, seriously, this one little step is going to save you a lot of trouble later, so just do it.
Scrub and wash the potatoes of any dirt/sprouts. Slice off a thin end along any long side so that the potato does not roll off the table when you further dissect it. Now cut the potato at 3-4mm intervals stopping about a cm above the base.
Cut up the garlic and butter into real thin slices. The hardened butter should make this a relatively easy task. Working quickly, stuff the little bits between each layer. The more, the merrier. Remember, the majority of the flavor is a result of these little tasty bits so you want to stuff as much of them as you can taking care not to break the potato while doing so.
Place the stuffed potatoes on a baking sheet/aluminum foil and give them a good sprinkle of coarse salt and pepper. Drizzle with olive oil and insert the tray in a 225C/440F oven for 55-60 mins. To get a really crispy exterior baste the potatoes with the olive oil that's collected in the pan at 20 minute intervals.
At the end of the baking period the potatoes should have a nice crunchy exterior and a soft center. Top with some homemade pesto or sour cream and bacon bits.
Revel in your gluttony as you forget about the other guests and devour them *all*.
* Parboil the potatoes to cut down on the baking time.
* Monitor the potatoes carefully towards the end. There's nothing worse than the taste of burnt garlic in these spuds.
* Those with an aversion to crispy skins(I know you don't exist) can peel the potatoes first.
* Trying to get that perfect cut down to the base? Place the potato on a wooden spoon and cut till you hit the wood.
* Ogle once more.