Combine cornmeal, flour, sugar, baking powder, salt, and pepper.
Whisk them together in a large bowl.
Make sure there are no lumps at all.
Crack the egg into the dry mixture.
Pour in the buttermilk slowly while stirring.
Mix until just combined and slightly thick.
Add the diced onions to your batter.
Stir gently until onions are evenly distributed.
Don't overmix or they'll be tough.
Pour oil into your pot or fryer.
Heat it to 350°F for perfect frying.
Use your thermometer to check the temperature.
Drop spoonfuls of batter into hot oil.
Fry for 2-3 minutes until golden brown.
Don't crowd the pot too much.
Remove hush puppies with your slotted spoon.
Place them on paper towels to drain.
Serve warm for the best taste!