Preheat the oven to 350 degrees F and prepare a 8.5 x 4.5 inch loaf pan by greasing and lining it with parchment paper for easy removal. Set aside. In a large mixing bowl, whisk together the flour, sugars, baking powder, baking soda, cinnamon, ginger, nutmeg and salt.
180 grams all-purpose flour, 4 grams baking powder, 6 grams baking soda, 1 gram salt, 3 grams cinnamon, 1 gram ginger, 1 gram nutmeg, 210 grams light brown sugar
In a separate bowl, add the oil, egg yolks, vanilla, sour cream, sourdough discard, and shredded carrots. Whisk until smooth.
120 grams oil, 2 eggs yolks, 80 grams sour cream, 4 grams vanilla extract, 120 grams sourdough discard, 200 grams grated carrots
Pour the wet ingredients into the dry ingredients and mix with a rubber spatula until just combined. Be careful not to overmix the batter, as this will lead to a dense quick bread.
Add chopped nuts or raisins, if desired and fold into batter.
optional chopped nuts or dried fruit
Long-ferment: Once you’ve mixed the wet and dry ingredients together, cover the batter and place in the fridge overnight. The following day, pour the batter into the prepared baking pan. Bake as normal.
Pour the quick bread batter into the prepared loaf pan, then bake for 55-65 minutes. If you notice the top of the bread is getting too brown, cover it with aluminum foil. The quick bread is done when a toothpick placed in the center comes out clean or with a few moist crumbs.
Transfer the quick bread on a wire rack to cool completely.