Preheat the oven to 450 degrees. Mix the dry ingredients together with a whisk until combined.
Bake in a greased muffin pan until golden brown about 15 minutes or until the cornbread springs back when pressed.
Heat a large sauté pan over medium heat. Melt the butter and sauté the onions, celery, and fresh herbs until the onions are softened and translucent, about 5-8 minutes.
Meanwhile, in a large bowl crumble 4 1/2 cups worth of cornbread with your hands or dice the cornbread into equal-sized portions.
You will have extra muffins leftover for this recipe depending on how much batter you scoop into the muffin tins. Just use about 4 1/2 cups worth of crumbled baked muffins for one casserole dish.