Homemade Potato Chips with Blue Cheese Dipping Sauce

Using a mandolin slicer set to the thinnest setting, sliced unpeeled potatoes. Place potato slices in a bowl of ice water to soak for 15 to 20 minutes, then drain and arrange in a single layer between sheets of paper towels or clean tea towels to dry completely. Fill a large, heavy saucepan with 2 to 3 inches of oil. Set over medium heat and monitor until it reaches 350 degrees F. Carefully drop in a few potato slices at a time, taking care not to overcrowd the pan. Fry for about 2 minutes, flipping once or twice, until chips are evenly golden in color. Transfer to a paper-towel lined baking tray to cool; sprinkle liberally with fine sea salt. Let oil come back to temperature before repeating with another batch of potato slices.

To prepare sauce, melt the butter in a saucepan over medium heat. Add the onion and cook until softened, about seven minutes. Whisk in the flour and cook for one minute. Slowly whisk in the milk. Continue to cook, whisking regularly, until thickened, about 5 minutes. Remove from heat and whisk in blue cheese until melted. Season to taste with cayenne and salt. Serve warm.