Preheat oven to 400°F (200°C). Whisk together cornmeal, flour, baking powder, and salt in a large bowl. In separate bowl, combine milk, vegetable oil, egg, and honey. Pour wet ingredients into dry ingredients and stir until just combined. Pour batter into greased 8-inch square baking pan and bake for 20-25 minutes until golden brown and toothpick comes out clean. Let cornbread cool completely, then crumble into bite-sized pieces.

While cornbread cools, prepare vegetables: wash and chop cherry tomatoes, bell peppers, red onion, and celery. Thaw frozen corn if using. Rinse and drain black beans. Chop fresh parsley.

Make dressing by whisking together mayonnaise, sour cream, apple cider vinegar, Dijon mustard, garlic powder, black pepper, and salt until smooth and well combined. Taste and adjust seasoning if needed.

Assemble salad in large clear bowl: start with layer of crumbled cornbread, spread one-third of dressing over cornbread. Add layers of vegetables - bell peppers, red onion, corn, black beans, celery, and tomatoes. Repeat layers until all ingredients are used, ending with final layer of dressing on top. Sprinkle with fresh parsley.

Cover salad with plastic wrap and refrigerate for at least 2 hours, or preferably overnight, to allow flavors to meld together and cornbread to absorb dressing. Serve chilled.