Preheat oven to 400°F. Line a standard 12-cup muffin tin with paper liners or grease it with cooking oil to prevent sticking.
In a medium-sized mixing bowl, combine the flour, baking powder, baking soda, salt, and spices. Set aside.
1 ¼ cups (150 grams) all-purpose flour, 1 teaspoon baking powder, ½ teaspoon baking soda, ½ teaspoon kosher salt, 1 teaspoon ground cinnamon, ½ teaspoon ground ginger, ¼ teaspoon ground nutmeg, ¼ teaspoon ground cloves
In a larger mixing bowl, whisk together the canola oil, brown sugar, and granulated sugar. Add the eggs and whisk until well combined. Incorporate the sourdough discard, applesauce, and vanilla extract, whisking until smooth.
½ cup canola oil, ½ cup (100 grams) brown sugar, ¼ cup (50 grams) granulated sugar, 2 large eggs, ½ cup (100 grams) sourdough starter discard, ¼ cup unsweetened applesauce, 1 teaspoon vanilla extract
Add the dry ingredients to the wet ingredients and fold together until just combined, taking care not to overmix. Gently fold in the grated carrots until they are evenly distributed throughout the batter.
1 cup (100 grams) freshly grated carrot
Evenly divide the batter among the 12 muffin cups in the prepared tin.
Bake the muffins in the preheated oven for 15-17 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Once baked, allow the muffins to cool in the tin for 5 minutes before transferring them to a wire rack to cool completely.
Store the cooled muffins in an airtight container for up to 3 days, or freeze them for up to 3 months.