01 - In a large mixing bowl, thoroughly whisk together the cornmeal, flour, baking powder, baking soda, kosher salt, granulated sugar, cayenne pepper (if using), and black pepper.
02 - In a separate bowl, beat the buttermilk, egg, and melted butter until uniformly incorporated.
03 - Pour the wet ingredients into the dry ingredients. Stir gently with a spatula just until the mixture is combined; avoid overmixing.
04 - Fold in the diced yellow onion, chopped chives or green onions (if using), and finely chopped jalapeño (if using). Allow the batter to rest for 5 minutes.
05 - In a heavy-bottomed pot or Dutch oven, heat approximately 2 inches of vegetable oil to 350°F (175°C).
06 - Using two spoons or a small ice cream scoop, carefully drop tablespoon-sized portions of batter into the hot oil. Fry in batches to prevent overcrowding the pot.
07 - Fry the hush puppies for 2 to 3 minutes per side, turning as necessary, until they achieve a deep golden brown color and crisp texture.
08 - Remove the cooked hush puppies with a slotted spoon and transfer them to a plate lined with paper towels to drain excess oil. Serve immediately.