Preheat oven to 400°F (200°C). If using a cast-iron skillet, place it in the oven while it preheats to get it nice and hot.
In a large bowl, whisk together cornmeal, flour, baking powder, baking soda, and salt.
In another bowl, whisk the sourdough discard, buttermilk, eggs, honey (or sugar), and melted butter.
Pour the wet ingredients into the dry and stir until just combined. Do not overmix.
If using a hot cast-iron skillet, carefully remove it from the oven and grease it with butter or oil. Pour the batter in and spread evenly. If using a baking dish, grease it before adding the batter.
Cook for 20-25 minutes or until golden brown and a toothpick inserted in the center comes out clean.
Let cool slightly before slicing. Serve warm with butter and honey.