In a large mixing bowl, whisk together the cornmeal, all-purpose flour, baking powder, salt, and ground red pepper.
Fold in the finely chopped onions, ensuring they are evenly distributed throughout the dry mixture.
In a separate bowl, whisk together the milk and the large egg until well combined.
Pour the wet ingredients into the dry ingredients and stir gently until just combined. Do not overmix; a few lumps are fine.
In a frying pan or deep fryer, pour enough vegetable oil to submerge the hush puppies (about 2-3 inches deep). Heat the oil over medium-high heat until it reaches 350°F (175°C).
Using a spoon or cookie scoop, carefully drop spoonfuls of the batter into the hot oil, frying until golden brown, about 3-4 minutes on each side. Remove with a slotted spoon and drain on paper towels.
Serve the hush puppies warm with your favorite dipping sauce or alongside a hearty meal.