1. Preheat your oven to 375 F (190 C). Line a 12-cup muffin tin with paper liners or grease it well with cooking spray.

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

3. In a separate medium bowl, whisk together the sourdough discard, milk, olive oil (or melted butter), and the large egg until well combined. The mixture should look uniform and slightly frothy.

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

5. Gently fold in the shredded cheddar cheese and chopped fresh chives (if using). Distribute them evenly throughout the batter without overworking it.

6. Divide the batter evenly among the 12 prepared muffin cups. Fill each cup about two-thirds full.

7. Bake for 20-25 minutes, or until the tops are golden brown and a wooden skewer or toothpick inserted into the center of a muffin comes out clean. The muffins should feel firm to the touch.

8. Let the muffins cool in the muffin tin for 5 minutes before transferring them to a wire rack to cool completely. They are best served warm.