Red, White, and Blue Potato and Beet Chips

Fill a large bowl with cold water. Using a mandoline or a very sharp knife, slice the baking and purple potatoes into 1/8-inch-thick rounds then transfer to the cold water to soak for 5 minutes. While the potatoes soak, slice the beets into 1/8-inch-thick rounds. Remove the potatoes from the water and transfer them to a paper towel–lined plate, patting them completely dry. Line a large baking sheet with paper towels. Fill a deep, heavy-bottomed medium saucepan (or deep fryer) with 4 inches of oil, leaving at least 3 inches between the oil and the top of the saucepan. Heat the oil over moderately high heat until a deep-fry thermometer registers 350 °F. Working in batches, use a slotted metal spoon or spider to carefully place the potato rounds in the hot oil. Fry, flipping as needed, until golden brown, 2 to 3 minutes. Transfer as done to the paper towel–lined baking sheet and immediately season with salt. Continue to fry the remaining potatoes, returning the oil to 350 °F between batches. Once all the potatoes are fried, fry the beets: Working in batches, use a slotted metal spoon or spider to carefully place the beet rounds in the hot oil. Fry, flipping as needed, until they begin to curl around the edges, 3 to 4 minutes. Transfer as done to the paper towel–lined baking sheet and immediately season with salt. Continue to fry the remaining beet rounds, returning the oil to 350 °F between batches. In a large bowl, toss together the potato and beet chips, season with additional salt if necessary, and serve. DO AHEAD: Potato and beet chips can be fried ahead and stored in an airtight container for 3 days.