Scrub and wash the russet potatoes. (You can peel the potatoes, if desired.)
Using a mandoline slicer with a crinkle-cut blade, holding the potato vertically, make a slice through the slicer. Turn the potato 90 degrees and make another slice. Continue to turn the potato after each slice until the entire potato is gone. (Turning the potato is the key to getting a waffle pattern, do not skip this step.)
Fill a large bowl with water and add the waffle fries to the water. Continue slicing all the potatoes into the water.
Add ice to the bowl and let the potatoes sit in the water for 15-20 minutes.
Drain the potatoes and transfer them to a towel or paper towel to fully dry the potatoes.
Fill a deep skillet or large pot with oil (about 2-3 inches deep) and heat on medium high heat until the oil reaches 350°F. (If you do not have a thermometer, test by adding a waffle fry to the oil and if it begins to bubble its ready.)
Once the oil is ready, carefully add the dried waffle potatoes to the oil and fry for about 4-5 minutes, until potatoes are golden and crispy. (Do NOT overcrowd, you might need to do it in batches.)
With a strainer, carefully remove the fries and transfer them to a cooling rack. Sprinkle with salt, pepper, and fry seasoning if desired and let cool for a couple minutes.
Serve with desired sauces and sides and enjoy.