Combine medium grind cornmeal and buttermilk in a large bowl and let sit for 10 minutes. Meanwhile, preheat oven to 375°F. Spray an 8x8-inch baking pan and set aside.
Mix together flour, sugar, baking powder, baking soda, and salt. Add to the cornmeal mixture along with the eggs and melted butter. Mix until thoroughly combined.
Transfer to the prepared pan and bake until golden and a toothpick inserted in the center comes out clean, about 25 – 30 minutes. Let cool slightly before serving.
For muffins:
Line a standard 12-serving muffin tin or a large 6-serving muffin tin with paper liners, then spray with pan spray. Bake for 15 minutes for standard muffins or 20 minutes for large.
