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square of pumpkin cake on wooden surface
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5 from 1 vote

Sourdough Pumpkin Sheet Cake with Cream Cheese Frosting

Sweet pumpkin spice mixed with tangy sourdough starter combine to form this moist, easy to make sourdough pumpkin cake.
Prep Time20 mins
Cook Time30 mins
cooling1 hr
Total Time1 hr 50 mins
Course: Dessert
Cuisine: American
Keyword: fall dessert, pumpkin cake, sourdough cake recipe, sourdough discard recipe, sourdough pumpkin cake
Servings: 20 slices
Calories: 421kcal
Author: Katie Shaw

Equipment

  • Rimmed sheet pan
  • Hand mixer
  • Large mixing bowl

Ingredients

Cake

  • 2 cups sugar
  • 1 cup vegetable oil
  • 2 cups pureed pumpkin 1 (15 ounce) can
  • 4 eggs
  • 1 ¾ cups all purpose flour
  • 2 teaspoons baking soda
  • 2 teaspoons baking powder
  • ½ teaspoon salt
  • 2 teaspoons cinnamon
  • ¼ teaspoon cloves
  • ¼ teaspoon allspice
  • 1/2 cup sourdough starter discard (unfed is fine)

Frosting

  • 10 tablespoons melted butter
  • 8 ounces cream cheese
  • 4 cups powdered sugar
  • 1 dash vanilla

Instructions

  • Preheat oven and prepare pan. Preheat oven to 350 with the rack in the center. Spray 10 x 15 jelly roll pan with nonstick cooking spray.
  • Combine wet ingredients (except the starter.) In a large mixing bowl beat the canned pumpkin, sugar, and oil until well combined, using an electric hand mixer on medium speed.  Add eggs, 1 at a time and beat until blended, scraping down bowl as necessary.
    mixing bowl with caned pumpkin and sugar
  • Mix dry ingredients in a separate bowl and add to the wet ingredients. Combine the flour, spices, baking soda, baking powder, and salt in a seperate mixing bowl. Add the dry ingredients to the pumpkin-sugar mixture, mixing on low until just combined.
    flour, spices in mixing bowl
  • Stir in the sourdough starter. Add the sourdough starter to the cake batter and stir by hand, scraping down the sides and bottom of the bowl to make sure everything is incorporated.
    sourdouugh starter being mixed into pumpkin cake
  • Bake and cool. Pour batter into prepared pan, gently spreading to smooth it out. Bake in preheated oven at 350 for 25-30 minutes.  Cool in pan on wire rack. Cover the cake with a clean tea towel after it has cooled for 15 minutes.
  • Make the frosting. After cake is cooled, make icing:  blend butter, melted cream cheese, and vanilla with mixer until fluffy.  Slowly add powdered sugar and beat until smooth. Do not frost the cake until it is fully cooled.
    cream cheese frosting in bowl
  • Serve. Spread icing on cake and serve directly out of the pan. Refrigerate any leftovers.

Notes

You can bake this cake in a rimmed sheet pan or a 13 x 9 baking dish.  
If your icing seems too thick, add a splash of milk.
🌻 Click here for more fall sourdough recipes here! 🌻

Nutrition

Calories: 421kcal | Carbohydrates: 56g | Protein: 3g | Fat: 21g | Saturated Fat: 13g | Polyunsaturated Fat: 2g | Monounsaturated Fat: 5g | Trans Fat: 1g | Cholesterol: 45mg | Sodium: 327mg | Potassium: 95mg | Fiber: 1g | Sugar: 45g | Vitamin A: 4264IU | Vitamin C: 1mg | Calcium: 52mg | Iron: 1mg