Place shredded sweet potato in colander and rinse under water, until the water runs clear. Squeeze out excess water and put in medium sized bowl.
Put all ingredients except for duck fat into the bowl with sweet potatoes. Mix until thoroughly incorporated. Put duck fat in cast iron skillet and heat at medium-high (325 degrees)
Once fat is heated measure 1/4c of sweet potato mixture and place into pan, then flatten with back of a spoon. Cook for 2-3 minutes on each side or until golden brown and crispy.
Drain on towel lined paper plate.