Preheat oven to 425° F. Prep a baking sheet by spreading about 1 teaspoon of oil to prevent the latkes from sticking.
Bring 4 cups of water to a boil. Add spiralized sweet potato and parsnip noodles to a large colander and pour boiling water over top. Drain noodles well and allow them to cool a bit — about 10 minutes or so. Scooping out a handful at a time, put the sweet potato and parsnip noodles into a clean kitchen towel and squeeze to remove as much liquid as possible.
Place squeezed noodles into a large bowl with eggs, scallions, garlic powder, salt and pepper. Mix well. Using a fork or your hands, scoop out some of the noodles and place onto the prepared baking sheet in the shape of a little nest. Each latke should use about 1/4 cup of the mixture and you should get about 12-14 latkes, depending on size. Press each latke down a bit with your hands. Place baking sheet in the oven and cook for 10 minutes. Remove sheet from oven, flip latkes over and cook for another 10 minutes until latkes are golden brown in color (the edges might get extra brown). Remove from oven and serve with apple sauce and plain greek yogurt (or sour cream).
Alternatively, you can cook the spiralized latkes in a skillet. Heat a little oil (about 1 teaspoon) in a medium sized skillet over medium heat. Once oil is hot, use a fork or your hands to scoop out some of the noodles and place in the skillet in the shape of a little nest. 2-3 latkes should fit in your skillet at one time. Cook on one side for about 3-4 minutes until golden brown. Press latkes down with your spatula to flatten a bit, flip and cook for another 3 minutes. Remove latkes from the pan and enjoy.