In a large bowl, combine flour, cornmeal, baking powder, salt, sugar, onion powder, black pepper, and optional cayenne.
Whisk dry ingredients to combine.
Grate a medium onion on the box grater over a dish or bowl. Set aside.
In a small bowl, add one cup milk, 1 egg, 1/3 c of the grated onion, and 1 T of the leaked onion juice. Whisk to combine.
Add the wet ingredients to the dry ingredients and stir to combine.
Cover the batter with plastic wrap and put in the refrigerator to chill for 30 minutes.
While the batter is chilling, add the oil to your dutch oven or fryer, and preheat to 375°F.
When batter has chilled and oil is hot, use a small cookie scoop to drop batter into the oil.
Drop 8-10 scoops into the oil at a time. They will sink--this is okay! They will rise to the top of the oil as they begin to cook.
Fry to a deep golden brown.
Continue to fry in batches until the batter is gone.
Serve warm with your favorite ketchup or tarter sauce.