In a bowl, combine zucchini, onion and egg. Add soy powder or flour, one tablespoon at a time, until mixture holds together. (Sometimes I have had to add a little more.) Stir in cheese, salt and pepper.
Melt butter in skillet over medium heat. Drop batter by 1/4 cupfuls onto skillet and flatten with spatula. Cook until crispy and brown, turn and cook the other side. Make sure you don't turn them too soon or they will fall apart.