Pour oil to a depth of 3 inches in a dutch oven; heat to 375° F. (See Note 2)
Whisk together cornmeal, flour, sugar, baking powder, and salt in a medium bowl. Add onion; stir to combine.
Add egg and buttermilk; stir just until moistened. Let stand 10 minutes.
Drop batter by rounded tablespoonfuls into hot oil, and fry, in 3 batches for 2 to 3 minutes per side or until golden brown. (See Note 3)
Remove from oil; drain on wire rack set inside rimmed baking sheet.
Keep warm in 200° F oven.
Yield: 1 ½ to 2 dozen Southern Hush Puppies.
