Best-Ever Cornbread

Preheat oven to 400° and grease a 9"-x-13" baking pan generously with butter. In a large bowl whisk together cornmeal, flour, brown sugar, baking powder, baking soda and salt. In another large bowl, whisk together milk, buttermilk, eggs, and melted butter. Add wet ingredients to dry ingredients and stir with a fork until just incorporated. Pour batter into prepared baking dish and bake until top is golden and a toothpick inserted into the center comes out clean, 20 to 25 minutes.  Let cool slightly before serving.