Preheat the oven to 250 degrees F. Arrange the Sour Cream Cornbread cubes on a baking pan in a single layer and bake until fairly dried out, about 30 minutes.
Meanwhile, toss together the tomatoes, celery, scallions, oil, vinegar, 1/2 teaspoon salt and a few grinds of black pepper. Let stand at least 10 minutes. Add the cornbread and basil and toss again to coat. Serve immediately.
Sour Cream Cornbread:
Preheat the oven to 450 degrees F. Spray a well-seasoned 10-inch cast-iron skillet with cooking spray.
In a medium mixing bowl, combine the cornmeal mix, creamed corn, sour cream, oil and eggs. Pour the mixture into the skillet and bake until lightly browned, about 30 minutes.