In a frying pan add 3 Tablespoons cold water, squash, onions (if used), and a light sprinkle of non- Iodized salt. Cook on medium to low heat until squash are tender when poked with a fork. Onions should be translucent (clear) and soft. Drain any remaining water off. Usually the water is cooked out and pan is dry when veg are done, depending on how thick the slices are.
Put squash blend in a bowl and gently mash with the back side of a fork. Stir in the beaten egg. Add flour and baking powder. Use a spatula to fold ingredients together well. Mixture should be about the consistency of biscuit dough.
Heat the pan until warm, add oil until hot. Drop large serving spoon size amounts in hot oil, about 350 degrees F (or 176 degrees C). When edges are browning, flip the fritter lightly and mash the top down flat to cook evenly. Pull out after about two minutes and drain on a paper towel. Serve room temperature or warm for best flavor.