Wash the okra thoroughly under cold water. Trim the stems and tips, then slice into ½-inch rounds.
Pour buttermilk into a medium bowl and add the sliced okra. Ensure all pieces are submerged and allow to soak for 15-30 minutes.
In a large bowl or paper bag, combine cornmeal, flour, salt, pepper, garlic powder, and cayenne if using. Whisk or shake to blend thoroughly.
In a large, heavy-bottomed skillet or cast-iron pan, pour oil to a depth of about ½ inch. Heat over medium-high heat until the oil reaches 350°F (177°C).
Working in batches, remove okra from the buttermilk, allowing excess to drip off, then dredge in the cornmeal mixture. Press the coating gently onto each piece to ensure even coverage.
Carefully add the coated okra to the hot oil in a single layer, being careful not to overcrowd the pan. Fry for 3-4 minutes until golden brown, turning occasionally for even cooking.
Using a slotted spoon, transfer the fried okra to a paper towel-lined plate. While still hot, sprinkle with additional salt if desired.
Serve immediately for maximum crispiness.