Sourdough Discard Carrot Cake
This sourdough discard carrot cake is incredibly moist with a gentle tang from the discard, warm cinnamon spice, tender shredded carrots, crunchy toasted walnuts, and plump raisins, all wrapped up in a fluffy cream cheese frosting.
Equipment
- 9-inch round cake pans - Set of 2
- Box grater - or food processor with shredding blade
- Large mixing bowls - 2 needed
- Whisk
- Rubber spatula
- Electric hand mixer - for the frosting
- Wire cooling rack
- Offset spatula - for smooth frosting application
- Measuring cups and spoons
- Parchment paper
- Pastry brush - for greasing pans
- Kitchen scale - optional, for dividing batter evenly
- Serrated knife - optional, for leveling cake layers
Ingredients
- 2 cups all-purpose flour - 250g
- 1 tsp baking soda
- 1 tsp baking powder
- 0.5 tsp fine salt
- 2 tsp ground cinnamon
- 0.5 tsp ground nutmeg
- 0.25 tsp ground ginger
- 1 cup granulated sugar - 200g
- 0.5 cup light brown sugar - 100g, packed
- 3 large eggs - room temperature
- 1 cup neutral vegetable oil - 240ml
- 2 tsp pure vanilla extract
- 0.5 cup sourdough discard - 120g, unfed, room temperature
- 2.5 cups freshly grated carrots - 250g, about 4 medium carrots, packed loosely
- 0.5 cup raisins - 75g
- 0.5 cup walnuts - 60g, roughly chopped, plus more for garnish
For the Cream Cheese Frosting
- 16 oz full-fat cream cheese - 450g, softened to room temperature
- 0.5 cup unsalted butter - 113g, softened to room temperature
- 3 cups powdered sugar - 360g, sifted
- 2 tsp pure vanilla extract
- salt - pinch
Instructions
- Preheat oven to 350°F (175°C). Grease two 9-inch round cake pans and line bottoms with parchment paper.
- Peel and grate carrots using a box grater or food processor until you have 2 1/2 cups (250g). Set aside.
- In a large bowl, whisk together flour, baking soda, baking powder, salt, cinnamon, nutmeg, and ginger.
- In another bowl, whisk granulated sugar, brown sugar, and oil until combined. Add eggs one at a time, then vanilla, and finally sourdough discard, whisking until smooth.
- Pour wet into dry and fold gently with a spatula until just combined. Do not overmix.
- Fold in grated carrots, walnuts, and raisins until evenly distributed.
- Divide batter evenly between prepared pans. Bake for 30-35 minutes, until toothpick comes out clean.
- Cool cakes in pans for 10 minutes, then turn out onto wire racks to cool completely.
- Beat cream cheese and butter with hand mixer until smooth. Add vanilla and salt. Gradually beat in powdered sugar until fluffy.
- Place one cooled layer on a plate. Spread with frosting. Top with second layer. Apply crumb coat, chill 15 minutes, then finish frosting. Garnish with walnuts.
Notes
- Room temperature ingredients: Set eggs and sourdough discard out 30-45 minutes before baking for best texture.
- Grate your own carrots: Pre-shredded carrots are too dry and coarse. Freshly grated carrots hold more moisture and integrate better into the batter.
- Do not overmix: Once flour is added, mix only until just combined to avoid a dense, tough cake.
- Toast walnuts: Spread walnuts on a baking sheet and toast at 350°F (175°C) for 7-8 minutes to deepen their flavor before adding to the batter.
- Cool completely before frosting: Warm cake will melt cream cheese frosting. Allow 1-1.5 hours for full cooling.
- Crumb coat: Apply a thin layer of frosting and refrigerate for 15 minutes to lock in crumbs before final frosting.
- Storage: Store frosted cake covered in the refrigerator for up to 5 days. Flavor improves after day one.
- Make ahead: Unfrosted cake layers can be wrapped and frozen for up to 3 months. Thaw overnight before frosting.
- Sheet cake option: Pour all batter into a 9x13-inch pan and bake at 350°F (175°C) for 38-42 minutes.
- Variations: Fold in 1/2 cup crushed pineapple, shredded coconut, or orange zest for a twist. Add 1/2 tsp cinnamon to the frosting for extra spice.