Puncture sweet potatoes several times with a fork. Cook in microwave on High for 5 minutes. Flip and cook until potatoes are easily pierced with a fork, about 3 to 5 more minutes; cool. Peel skin off and cut sweet potatoes into large chunks.
Mash garbanzo beans with a fork or potato masher in a bowl.
Stir sweet potatoes and egg into mashed garbanzo beans to form a smooth consistency.
Stir 2 cups flour, garlic powder, cumin, and coriander into sweet potato mixture to form a cookie dough consistency. Adjust with more flour if necessary.
Roll the dough into 1-inch balls and place on prepared baking sheet. Slightly flatten balls into patties.
Bake in the preheated oven until golden brown, about 30 minutes, flipping after 15 minutes.
