Mix half a cup of amaranth grains with a cup and a quarter of water, bring to a boil, lower the heat, and cook for about 20 minutes. You will get thick porridge, like oatmeal. Set aside.
Defrost green peas: Put the peas in a small bowl, pour boiling water until covered, cover the bowl, and set aside.
Cook The Sweet Potatoes: Peel the sweet potatoes and cut into dice about 2 cm (3/4 inch) in size, transfer to a saucepan, cover with water, bring to a boil, lower the heat and cook until soft. Strain, leave in the colander for about 5 minutes to drain the liquids. Transfer to a bowl and mash the sweet potatoes. (It's OK if some dice will escape the mashing). Allow cooling for a few minutes.
Strain the peas and add them to the sweet potato bowl; add the cooked amaranth, chopped coriander, tapioca starch, cornflake crumbs, grated ginger, minced garlic, almond butter, curry powder, salt, and chili flakes. Mix well with clean hands. Taste and adjust seasoning if necessary. Cover and refrigerate for about an hour so that the mixture sets and we can work with it easily.
Preheat the oven to 190 degrees Celsius (374 Fahrenheit)
Line a pan with baking paper. Spray or brush the baking paper with oil.
Form patties with wet hands about 4 cm (about 1.6 inch) in length and about 1 cm thick (about 0.5 inch); place the patties in the pan lined with the greased baking paper. Make sure to keep a 2-3 cm distance from one another. Brush or spray the top of the pancakes with oil.
Place in the hot oven and bake for about 30 minutes until golden. Turn over and bake for another half hour until nicely golden. Remove from the oven and cool for 3-5 minutes before removing the patties from the pan.