1. 1. Prepare Your Oven and Muffin Tin: Preheat your oven to 375 F (190 C). Line a 12-cup muffin tin with paper liners or grease it thoroughly with non-stick spray. This ensures easy removal and cleanup.

2. 2. Combine Dry Ingredients: In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, brown sugar, baking soda, cinnamon, nutmeg, ginger, and salt. Make sure there are no lumps, especially in the brown sugar.

3. 3. Mix Wet Ingredients: In a separate medium bowl, whisk together the sourdough discard, unsweetened applesauce, vegetable oil, eggs, and vanilla extract until well combined and smooth.

4. 4. Combine Wet and Dry Mixtures: 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 more tender muffin. Overmixing can result in tough muffins.

5. 5. Fold in Carrots and Nuts: Gently fold in the grated carrots and optional chopped walnuts or pecans until evenly distributed throughout the batter.

6. 6. Fill Muffin Cups: Divide the batter evenly among the 12 prepared muffin cups, filling each about two-thirds full.

7. 7. Bake Until Golden: Bake for 20-25 minutes, or until a wooden skewer or toothpick inserted into the center of a muffin comes out clean. The tops should be golden brown and spring back when lightly touched.

8. 8. Cool Before Serving: Remove the muffin tin from the oven and let the muffins cool in the tin for 5 minutes before transferring them to a wire rack to cool completely. This helps prevent them from getting soggy.