1. Preheat Your Oven and Skillet: Place a 9-inch cast iron skillet in your oven and preheat to 400 F (200 C). Allowing the skillet to heat up in the oven ensures a wonderfully crispy crust on your bread.

2. Combine Dry Ingredients: In a medium bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt until well combined. This ensures the leavening agents are evenly distributed throughout the dough.

3. Mix Wet Ingredients: In a separate large bowl, combine the sourdough discard, milk, 2 tablespoons of olive oil, chopped rosemary, chopped thyme, and minced garlic (if using). Stir until everything is thoroughly mixed.

4. Combine Wet and Dry: Pour the dry ingredients into the wet ingredients bowl. Using a spatula or wooden spoon, mix until just combined. Be careful not to overmix; a few lumps are perfectly fine and will result in a more tender bread. Overmixing can develop the gluten too much, leading to a tougher texture.

5. Add Dough to Hot Skillet: Carefully remove the hot cast iron skillet from the oven using oven mitts. Add a small drizzle of olive oil to the hot skillet and swirl to coat the bottom and sides. Immediately transfer the dough into the hot skillet, spreading it gently and evenly with your spatula. The hot skillet will start to sizzle slightly, which is exactly what you want for that golden crust.

6. Bake Until Golden: Place the skillet back into the preheated oven and bake for 15-20 minutes, or until the top is golden brown and a wooden skewer or toothpick inserted into the center comes out clean. The internal temperature should reach around 200-210 F (93-99 C).

7. Cool and Serve: Once baked, carefully remove the skillet from the oven. Let the bread cool in the skillet for about 5 minutes before carefully transferring it to a cutting board. Slice into wedges and serve warm.