Preheat oven to 450°F.
Using a mandolin, slice potatoes into 3mm rounds.
Add potatoes, truffle oil, and truffle salt to a large bowl, mix until well combined.
Add 1 teaspoon of truffle oil to a medium cast iron skillet.
Assemble galette by layering potato slices in three rings covering the bottom of the pan.
Continue arranging potatoes until you have three layers of rings.
Add skillet to oven and bake for 20 minutes.
Check galette after 20 minutes, if the top is brown cover it with foil and cook for an additional 5 minutes, if it needs to brown more cook for an additional 5 minutes uncovered.
Remove from oven, loosen edges with a spatula and flip onto a serving plate.