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

In a medium bowl, whisk together mayonnaise, sour cream, and ranch dressing mix until smooth and well combined.

In a large trifle bowl or clear glass serving dish, start with half of the crumbled cornbread as base layer. Top with half of the pinto beans, followed by half of the corn. Spread about one-third of the dressing mixture over the corn layer. Continue with layers of tomatoes, red onion, bell pepper, and turkey ham. Add remaining cornbread, then the rest of the beans and corn. Spread remaining dressing over the top.

Sprinkle shredded cheddar cheese evenly over the top layer. Cover with plastic wrap and refrigerate for at least 2 hours, or preferably overnight. Just before serving, garnish with fresh parsley.