Grandma looked at the horizon, drew a deep breath and said, “This is Thunder Cake baking weather, all right. Looks like a storm coming to me.”

When you see clouds gathering in the distance and you can feel the change in the wind, it’s time to gather your ingredients. According to the story by Patricia Polacco, it’s only a REAL Thunder Cake if it’s in the oven before the rain falls. This tale of a little girl’s quest to overcome her fear of thunderstorms contains a recipe for chocolate cake to bolster your spirit when facing your fears. CRASH! BOOM! Let’s get baking!

ingredients for thunder cake as described below


Cake Batter:

  • 1 US cup shortening (191 g)
  • 1 & 3/4 US cup granulated sugar (350 g)
  • 1 teaspoon vanilla extract (0.15 oz/4.25 g)
  • 3 large eggs
  • 1 US cup cold water (8.35 ounces, 237 ml)
  • 1/3 US cup tomato puree/passata (75 g)
  • 2 & 1/2 US cup cake flour (325 g)
  • 1/2 US cup cocoa powder (59 g)
  • 1 & 1/2 teaspoon baking soda (7.2 g)
  • 1 teaspoon salt (6 g)


  • 5 1/2 ounces unsalted butter, room temperature (156 g)
  • 1 ounce mayonnaise (28 g)
  • 3 ounces semisweet chocolate, melted and cooled slightly (85 g)
  • 8 ounces powdered sugar (227 g)
  • Pinch kosher salt

The recipe for this cake can be found in any copy of Thunder Cake but it is also copied at this website [LINK].

Thunder Cake Instructions:

Preheat your oven to 350°F/177°C/Gas Mark 4. Grease and flour two round cake pans, 9 in/23cm.

mixer creaming together ingredients to a smooth, even texture

Cream together the shortening and sugar. Separate your eggs. Add the egg yolks and vanilla to your creamed mixture.

Mix in the cold water and pureed tomatoes. Beat the egg whites until they are stiff and fold into the egg/tomato mixture.

mixture with wet ingredients and cocoa added, mixed until a smooth texture

Sift together the cake flour, cocoa, baking soda, and salt. Mix the dry mixture into the wet.

2 cake pans with reddish brown cake, baking in the oven

Pour batter evenly into cake pans. Bake for 35 to 40 minutes. Let cakes cool on wire racks before frosting.

While the cake is baking, prepare your chocolate frosting. Store-bought is fine or your own favorite chocolate buttercream frosting. I used this recipe:

Frosting Instructions:

Melt chocolate in a double boiler or microwave.

Beat the butter and mayonnaise until light and fluffy [if using a stand mixer, mix on high for 3 to 4 minutes]. Slowly add the melted chocolate until fully incorporated, stopping to scrape down the sides of the bowl.

Turn off the mixer and add ⅓ of the sugar. Mix on LOW (or else it’ll go up in a cloud!) until combined. Repeat until all the sugar is added and combined.

frosting ingredients mixed to a creamy texture

Add the salt and continue to beat until the frosting is smooth and has slightly lightened in color.

You may decide to top your cake with fresh fruit, like strawberries or raspberries. While your cakes are cooling, wash and cut your fruit.

finished cake with chocolate frosting and fresh raspberries for toppings

Once your cakes are completely cooled, frost between the layers and on top and sides. Decorate with fresh fruit if desired.

By the time the storm has arrived, you should have a beautiful cake to enjoy during the downpour. You can also enjoy Patricia Polacco reading her story here:

Contributed bySteena AKA Lore Coordinator Steena
As Lore Coordinator, Steena is a spinner of tales and keeper of legends. She’s been a camper since the beginning (Troop Marshwiggle!) and has made friends with the bats and squirrels in the forest. If you’re looking for her around the campground, she’s probably eating pie down by the lake.