A while back Ann Burrell on her TV show made a Potato Crusted Halibut. I made this version using Mahi Mahi from Trader Joe's. A much more available fish in these parts but I think the result was about the same.
Basically you sliced the spuds as thin as possible with the mandolin and then laid them out in overlapping layers on parchment paper, place your fish in the center and wrapped it all up like a package using the paper to help roll the fish. Yukon Gold potatoes were used and on her show she used an infused olive oil to brush the potatoes. The infusion was made with bay leaf, garlic, thyme, lemon zest and fennel seed. This was brought to a boil then set aside for an hour to infuse.