Note: Special equipment is needed for this recipe: a V-slicer or mandoline and deep-fry thermometer.
Wash the vegetables and dry very well.
In a small bowl combine the garlic, rosemary and salt.
Warm the oil in a large pot over high heat to 350 degrees F.
Meanwhile, trim 1 inch off the end of each sweet potato.
Using the V-slicer or mandoline, slice the sweet potatoes into very thin slices, about 1/8-inch thick.
Trim 1 inch off the root end of the beets.
Using the V-slicer or mandoline, slice the beets into very thin slices, about 1/8-inch thick.
When the oil is hot add about a quarter of the sweet potato slices.
Let fry until golden and the bubbling has almost completely subsided, about 2 to 3 minutes.
Using a mesh sieve or slotted spoon remove the chips to a paper-towel-lined baking sheet.
Sprinkle with some of the garlic, rosemary, and salt mixture.
Continue with the remaining sweet potatoes.
Transfer to a serving plate.
Next, fry 1/4 of the beets.
Let fry until curled at the edges and most of the bubbling has subsided, about 3 to 4 minutes.
Transfer the beets to another paper-towel-lined baking sheet and sprinkle with salt mixture.
Continue with the remaining beets.
Let cool and transfer to a serving plate.