Take the stems off your onions and peel the skin. Slice into 1.5” thick rings making sure to separate them into individual onion rings. Put the rings in ice water to soak.
Preheat your fire to a medium high temperature (around 375-400F). Add a deep dish cast iron skillet or dutch oven over the fire with at least 2-3” of frying oil in the cast iron. Bring the oil up to 375F.
In a bowl, add 1.5 cups of your flour along with the cornstarch, salt, pepper, garlic and cayenne. Slowly add in your beer, while also mixing, until you have a smooth batter with the consistency like pancake batter.
Add the rest of your flour to another separate bowl.
Pull the onion rings out from the fridge. Drain the water and gently pat the onion rings dry.
Begin by adding one onion ring to the flour and coat evenly. Next, add it to the beer batter and coat evenly.
Take the battered onion ring and add it directly to the frying oil to cook for about 2 minutes per side or until golden brown. Repeat this process until all the onion rings are battered and fried.
You can cook 3-5 onion rings at a time, but try not to overcrowd the skillet. Once the onion rings are done, place on a wire baking sheet with paper towels underneath.
Serve with your favorite dipping sauce and enjoy!