Prep oven and pan. Preheat the oven to 400℉. Line an 8x8 pan with a piece of parchment and set aside.
Mix dry ingredients. Add the cornmeal, flour, sugar, baking powder, and salt to a mixing bowl. Using a whisk, stir to combine.
Add wet ingredients. Add the milk, oil, sourdough starter, and egg to the bowl with the cornmeal mixture. Stir to combine.
Bake. Pour the batter into the prepared 8x8 pan and bake at 400℉ for 20-22 minutes. To check doneness, insert a toothpick into the center of the cornbread. If it comes out clean, remove it from the oven.
Brush with butter (optional). Brush the top of the cornbread with melted butter.
Cool and serve. Allow it to cool for 10 minutes. Divide into 9 equal pieces and serve with butter and honey.
Notes
Brushing the top of the cornbread with melted butter will help keep the cornbread moist.