Place a heavy pot over medium-high heat with at least an inch of vegetable oil. Heat oil to 350 degrees F; it is important to monitor and maintain the temperature, or the soy flour breading and your oil will burn. (Portable deep fryers at home are great for this.)
In a medium bowl, mix the eggs and cream to make an egg wash. In a separate larger bowl, mix the breading ingredients together.
Peel and slice the onions in thick slices and carefully separate the rings. Then dip individual onion rings in the breading, then the egg wash, and then back in the breading again, making sure to coat well. Pat off any excess breading and carefully place into hot oil, in batches as necessary, and fry until golden brown and crisp, just 1 to 2 minutes. Remove and drain on paper towels. Serve immediately
Soy flour is made from toasted soybeans and has already been "cooked." Therefore it has a tendency to brown faster than plain flour when frying.
Try this same breading for baked pork chops, okra, mozzarella sticks, mushrooms, chicken, and eggplant.