In your cast iron skillet, melt the lard. Once melted, pour into a mixing bowl.
Add sugar, eggs, and sourdough discard to the bowl. Mix until fully incorporated, then stir in the milk.
Gradually mix in the whole wheat flour, white flour, cornmeal, baking powder, baking soda, salt, and any optional additions you desire.
Mix all the ingredients together until a smooth batter forms. Cover the bowl and let it rest for 15 minutes at room temperature or refrigerate for 24 hours for a cold ferment.
When you're ready to bake, preheat your oven to 375°F (190°C). Prepare a 10" cast iron skillet by generously greasing with lard (you can spread what remained from melting) and flouring it.
Pour the batter into the prepared baking dish, spreading it evenly.
Bake for around 20-25 minutes, or until the top is golden and crisp, and a toothpick inserted in the centrre comes out clean.
Allow the cornbread to cool in the baking dish for 10-15 minutes. Serve warm with chili!