If using frozen fillets, totally defrost then make sure they are dried with paper towel. defrosted. For fast defrosting, frozen fillets can be soaked in cool tap water.
Get out and measure your ingredients, including the peanut oil.
In a heavy frying pan, pour enough oil that reaches up to a ½ to ¾ of an inch up the sides of the pan. Turn heat to medium high.
Turn your oven to 200 degrees and place a rimmed baking sheet a wire rack on top.
Using a thermometer, oil should reach 350 degrees. If you don't own or use one, flick a little water into the oil, and if it sizzles instantly the oil is ready. My husband waits until the oil starts to shimmer and adds a little drop of pancake batter to it.. If it turns black right away, the oil is too hot. If the drop sinks to the bottom and stays there too long, the oil isn't hot enough. You know it's the right temperature when the drop goes to the bottom and quickly floats to the top and starts to sizzle around the edges. Then you're ready to fry your fish fillets or pieces!
In a medium sized bowl, make pancake mix according to package directions. Usually, it's 1 cup pancake mix to ¾ cup water or flat beer. If using beer instead of water, make sure beer is totally flat, with no bubbles at all. Combine and set aside in your fridge or make batter once oil is ready. The longer the baking powder in the pancake mix sits at room temperature, the more ineffective it becomes. I always make my batter right before I need it or refrigerate batter until needed.
Dip fillets into pancake batter, shake off the excess and gently lay into the hot oil.
Fry until golden brown, between 2-5 minutes, depending on how thick the fillet is.
Use a spatula and gently turn the fish over and cook for another 2-5 minutes.
Once a beautiful golden brown on both sides, move each piece into the oven while cooking the rest of the fish. Keeping the fish warm in the oven will help keep it crispy until you are ready to eat it.
When all cooked, serve at once with fresh lemon and tartar sauce. Enjoy every bite!