01 - Preheat oven to 400°F. Grease an 8-inch square baking pan. In a large bowl, combine cornmeal, flour, sugar, baking powder, and salt. In a separate bowl, whisk together buttermilk, eggs, and melted butter. Pour wet ingredients into dry ingredients and mix until just combined. Pour batter into prepared pan and bake for 20-22 minutes until set and golden. Let cool completely, then crumble into a large bowl.
02 - In a skillet, melt 2 tablespoons butter over medium heat. Add onion and celery; cook until softened, about 5-7 minutes. Stir in garlic, sage, thyme, pepper, and salt; cook 1 minute more. Add vegetable broth and bring to a simmer. Remove from heat and stir in parsley.
03 - Pour the sautéed vegetable mixture over the crumbled cornbread. Mix thoroughly until cohesive and moist but not wet. With damp hands, form mixture into 16 golf ball-sized balls. Chill in the refrigerator for 15 minutes to help them hold their shape.
04 - Set up a breading station: Place beaten eggs in one shallow bowl, panko breadcrumbs in another. Dip each ball in egg, then roll in panko, pressing gently to adhere.
05 - Heat 2 inches of vegetable oil in a deep skillet or Dutch oven to 350°F. Fry balls in batches, turning as needed, until deeply golden and crispy, about 3-4 minutes per batch. Drain on paper towels. Serve hot as an appetizer or side.