1. Preheat your oven to 375 F (190 C). Lightly grease a 9-inch cast iron skillet or an oven-safe baking dish with a little olive oil.

2. In a large mixing bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt. Make sure there are no lumps and the ingredients are evenly distributed.

3. In a separate medium bowl, combine the sourdough discard, milk, and 1/4 cup of olive oil. Whisk until well combined and smooth. The discard should be fully incorporated.

4. Pour the wet ingredient mixture into the dry ingredient mixture. Stir with a spoon or spatula until just combined. Be careful not to overmix; a few lumps are perfectly fine and will lead to a tender bread.

5. Gently fold in 3/4 cup of the shredded cheddar cheese into the batter. Reserve the remaining 1/4 cup for topping.

6. Pour the batter into your prepared skillet, spreading it evenly with the back of a spoon or spatula.

7. Sprinkle the remaining 1/4 cup of shredded cheddar cheese over the top of the batter. Place the skillet in the preheated oven and bake for 20-25 minutes, or until the bread is golden brown on top, a toothpick inserted into the center comes out clean, and the cheese is bubbly and slightly browned.

8. Once baked, carefully remove the skillet from the oven. Let the bread cool in the skillet for about 5-10 minutes before slicing and serving. This helps it set and makes it easier to cut.