Here's the recipe:
4 Potatoes (I used Russets)
1 stick of Butter (Frozen)
Parmigiano-Reggiano hard cheese, Sliced thinly
Shredded Cheddar Cheese
Oven = 400 F
Note - Looking at the Pin or the other website helps a lot... the instructions posted have a lot of pictures. Read my tips below though!
Slice the potatoes, but not all the way through. It's recommend to use wooden spoons, I used rubber. With my sharp knife it wasn't the best idea. (My spoons have knicks now) The best trick I saw is to use wooden chopsticks! Those would be perfect and I will use them next time.
Slice the butter and cheese. Place the slices in the pre-sliced potato, alternative between the butter & cheese. The potato will start to curl, and be careful not to break it!
Place potatoes on a cutting board/plate/sink and drizzle with olive oil. I drizzled the EVOO when the potatoes were on the cookie sheet and it made a huge mess to clean up later. Sprinkle with salt/pepper/garlic/whatever spices you want.
Cook the potatoes for 45 minutes. Pull out and drizzle with cream or milk. (I used about 1/4 cup for 4 potatoes.) Sprinkle with cheddar cheese and put back in the oven for about 15 minutes. They were delicious!!