Sourdough Vegan Crazy Cake (Episode 4)


In this episode, we learned that a major contributor to climate change happens right in our kitchen: food waste. 

And it’s a tricky nut to crack, because waste is built into our food system at so many different points. Solving it will require ending what author and episode guest Amanda Little called “the perfect produce epidemic,” overhauling America’s confusing system of “best by” and “use by” labels, and yes – running more efficient kitchens.

If you’re a bread baker, one of the most regular sources of waste is your trusty, hungry, has-to-be-fed-every-day sourdough starter. If you’re baking bread regularly, you could waste pounds of flour in a month. I know I have. But luckily, the Zero Waste Chef Anne-Marie Bonneau has ideas for how to use up the discard – deliciously. She generously shared her recipe for a variation of Crazy Cake called “Sourdough Discard Chocolate Cake,” reprinted below with permission.

Not a bread baker? Worry not! If you’d like to bake a sourdough-free version of Crazy Cake, we’ve got that too, courtesy of my family, who’s made our version of Crazy Cake for all manner of celebrations for generations. Sourdough or no, Crazy Cake is a great way to “shop your kitchen first,” as Anne-Marie advises. It’s made with pantry ingredients you likely already have on-hand – no trip to the store for new stuff required. Both recipes are below. If you’d like, try both and compare! Having two cakes is literally never a problem.

Anne-Marie's new cookbook, The Zero Waste Chef, is choc-full of ways to make the most of food in your kitchen – including several recipes for how to make delicious use of leftover sourdough starter, or "discard."

The Zero Waste Chef's Sourdough Discard Vegan Crazy Cake

Anne-Marie’s recipe and recipe notes are reprinted in full, with permission, below.

Servings: 12


  • 1 cup all-purpose flour
  • 1 cup packed brown sugar
  • 1/4 cup cocoa powder
  • 1 teaspoon baking soda
  • 1/2 teaspoon salt
  • 1/2 cup unfed discarded starter (straight from the refrigerator)
  • 1/2 cup cold water
  • 1 tablespoon vinegar (white, cider, or strong homemade)
  • 2 teaspoons vanilla extract
  • 1/3 cup olive oil (plus more for greasing the pan)
  • 1 portion buttercream frosting, if desired


  1. Preheat oven to 350 degrees Fahrenheit. Generously grease an 8-inch by 8-inch glass or metal baking pan.
  2. Combine flour, brown sugar, cocoa powder, baking soda, and salt in a medium bowl. 
  3. Combine unfed discarded starter, water, vinegar, vanilla extract, and olive oil in a separate small bowl.
  4. Add wet ingredients to dry ingredients. Stir until moistened and pour batter into prepared pan. 
  5. Bake for 25 to 30 minutes or until a fork inserted in the center of the cake comes out clean. Cool the pan on a baking rack. 
  6. If frosting the cake, allow it to cool completely first. 


  1. This cake tastes delicious with 1/4 cup of chocolate chips or so added to it. Mix them in with the dry ingredients. If you add chocolate chips, reduce the sugar by about 1/4 cup.
  2. You can also make cupcakes. Divide batter among only 9 muffin cups of a standard, 12-muffin-size pan. Bake for 15 minutes or until a fork inserted in the center of the cupcake comes out clean. 
  3. All of my (Anne-Marie’s) sourdough recipes use a 100 percent hydration sourdough starter, meaning the starter contains equal parts water and flour by weight (not by volume). 
  4. If you don’t keep a sourdough starter, increase the flour to 1 1/2 cups and the water to 1 cup. 
Naturally, I had to compare Anne-Marie's sourdough discard cake to a similar, but sourdough-free, version that's been in my family a couple generations. Anne-Marie's cake is on the left, and my mom's family's "Crazy Cake" is on the right. My mom and I taste-tested and... my mom preferred Anne-Marie's! Over her own family's recipe! But just slightly. They're both incredible. I think they each have their own merits.

The Auel Family Recipe for Crazy Cake

Servings: 8 if you like big pieces of cake. 12 if you’re more restrained. 

This recipe has been made in my mom’s family for at least a couple of generations. Eschewing butter and eggs for cheaper – and vegan – sources of fat and leavening, namely vegetable oil, vinegar, and baking soda, this one-bowl chocolate cake swept onto the scene during times of rationing and frugality, but it was so delicious and easy that it’s had culinary staying power. At least one of my mom’s siblings has it every year for his birthday, and it’s a regular at my family’s home when we need something sweet on the fly.


  • 1 ½ cups sifted flour
  • 3 Tb cocoa
  • 1 tsp baking soda
  • 1 cup sugar
  • ½ tsp salt
  • 5 Tb cooking oil
  • 1 Tb vinegar
  • 1 tsp vanilla
  • 1 cup water


  1. Preheat oven to 350 degrees F.
  2. Sift flour, cocoa, baking soda, sugar, and salt into a greased, 9×9 inch pan. (If you don’t want to be old-fashioned, you can also sift these ingredients into a separate bowl, and wait to pour everything into the bowl until you have the batter mixed. Your call.)
  3. Make three grooves in the sifted dry ingredients (either directly in the pan, or in the bowl if you’ve kept everything in a bowl), then pour oil, vinegar, and vanilla separately into each groove. 
  4. Pour water over all. 
  5. Beat with spoon or whisk until nearly smooth. 
  6. Bake at 350 degrees F for 30 minutes, or until a toothpick inserted in the center of the cake comes out clean.
The Auel family recipe for Crazy Cake
The bowl-free way you're supposed to mix the ingredients – right in the square pan! (But you could use a bowl, too.)

Episode summary

A major contributor to climate change happens right in our kitchens: food waste. But why is it so hard to solve? And how can home bakers bake it away, deliciously? In this episode, host Caroline Saunders traces the evolution of food waste in American cooking – and tips to solve it – with columnist and professor Amanda Little, climate expert Kari Hamerschlag, and cookbook authors Anne Byrn and Anne-Marie Bonneau. The Zero Waste Chef Anne-Marie Bonneau shares a recipe for sourdough discard chocolate cake, available on

More resources

Art by Megan Woodruff