Cut sweet potato into quarters. Grate (using the medium setting). Pat dry potatoes with a towel and place in a large mixing bowl. This helps remove some of the moisture and will prevent them from getting liquidy when cooking. Add to a large mixing bowl.
Peel and chop the onion into quarters. Place in a food processor and chop up into almost a liquidly / slushy consistency. Add onion to the mixing bowl.
Whisk 3 eggs and add them to the mixing bowl. Mix eggs, potato, and onion very well in the bowl.
Add cassava flour, tapioca flour, salt to taste, baking powder and any desired spices to the mix. I added a little bit of "chili lime seasoning" from trader joes for a kick. Again, mix all ingredients well until the flour is absorbed and the latke "batter" is ready.
Heat up a skillet / sauce pan / cast iron skillet with the avocado oil until slightly bubbly. BE CAREFUL, this is essentially deep frying and it can get spatter. I suggest using a spatter guard if you have one. Also, highly recommend avocado oil because its smoke point is super high (more than olive oil).
Using a spoon, scoop out from the mixture (half palm size) and form a ball in your hand. Add to to the skillet and push down slightly to flatten more with a spatula. Repeat until you fill the skillet (about 4 ) and let cook for about 3 - 4 minutes. Flip when the edge start to brown and cook for half the time on the second side.
Once ready, remove from skillet and place on dry rack with some paper towel / towel underneath to absorb any oil that drips.
Repeat this until all the batter is gone. This recipe makes about 8 - 10 latkes depending on how big you make them.
Enjoy hot with any toppings you like - sweet and savory are both delish. Traditionally, sour cream and apple sauce are the way to go. You can store in the fridge for 4 - 5 days or the freezer for 2 months.