Fried onion rings are a great "go-with" for many dishes. I've played with this somewhat and found this method to be pretty good.

1 very large onion - sliced 3/8"

In a zipper bag add the following:

1/2 pint of whipping cream or milk
1 tsp. Creole seasoning 
1/2 tsp. black pepper
1 tsp. garlic powder
sliced onion

Seal and mix well moving the bag around. Let sit in ice box for a few hours.

Next, mix the following:

1/2 cup of Bisquick
1/2 cup of cornstarch

Pour dry mix above into zipper-bag. mix around well. Pour all of this in a bowl. Now, you may have to add milk, or, add dry mix to get the right consistency to what is now the battered onions. Adjust the batter to where it looks like thin pancake batter. You will see that the batter sticks like glue to the onions. That's because of the cornstarch. 

Now you're ready to do the frying.

Mix together the following:

1 cup flour
1 cup cornstarch
1 tbs. Creole  seasoning
1/4 tsp. each of salt and pepper

This is your dry mix.

In a fryer heat a few inches of cooking oil to 365ºF. Fry 3 or 4 onions at a time depending on the width of the fryer. Just space them out evenly, and, watch your fire so the oil doesn't start smoking. Fry them for a few minutes on one side, flip them over for another minute then remove before the bubbling quits completely. Timing is a judgment call as you watch the bubbles.

After the first batch is done and cooled a little taste them. If they need a little seasoning, sprinkle on to taste. 

Enjoy....