This is my last blogging effort with zucchini, having chopped, grated, boiled, sautéed. and baked our neighbor’s zucchini in virtually every way I can think of. The beauty of this recipe is that it uses up a fair amount of zucchini and produces a moist cake that doesn’t taste like zucchini.

You will see clearly from the images, that I am a rank amateur when it comes to cake baking, but the opposing view is that anyone can bake this cake. Part of my problem may be that I revised a sheet cake recipe from a useful little baking book if you live at a high altitude, High Altitude Baking edited by Patricia Kendall and published by Colorado State University Cooperative Extension, 2003. If you live at sea level, you will probably need to increase the baking powder.

This post will also have some tips on what cookbooks describe as “that easy, no-fail American classic”, seven-minute frosting. The first time I ever attempted this recipe was when I was about 12 years old. I had decided to surprise my mother with a birthday cake since everyone else in the family got their own birthday cake made by her. After everyone had gone to bed, I moved utensils and ingredients for a cake into the garage. Everything turned out ok except for the seven-minute frosting which the next morning fell off the cake in great blobs. Since then I have tried making the frosting many times without success. Finally, I have learned that my failures can be traced to inadequate instructions. That deficit has been corrected by Ethan Becker in his complete revision of his grandmother’s classic. Check out his instructions in The All New Joy of Cooking, (Scribner, New York), page 1001

Here are Ethan Becker’s tips: 1) Use a stainless steel bowl or double boiler instead of glass as glass heats too slowly, and the top of the cooking frosting (actually a meringue) cools too quickly to cook completely. 2) Immerse the bowl or double boiler pot so that the water level is at the level of the frosting mixture. 3) Make sure the eggs are at room temperature before beginning the process. 4) Do not stop beating the mixture while it is in the hot water bath or the egg whites will overcook. 5) Use an instant read thermometer and be sure the mixture reaches 140° F. 6) Don’t add the vanilla or other flavorings until you have finished beating the frosting.

Chocolate zucchini cake with mocha seven-minute frosting

Chocolate zucchini cake with mocha seven-minute frosting

A piece of cake

A piece of cake


Chocolate Zucchini Cake


  • 2½ cups all-purpose flour
  • 1½ teaspoons baking powder (*NB: at sea level you may need to increase to 2 teaspoons)
  • 1 teaspoon baking soda
  • 1 teaspoon salt
  • ¼ cup unsweetened cocoa
  • ½ cup unsalted butter, softened
  • 1¾ cup sugar
  • 2 large eggs
  • ½ cup buttermilk
  • ½ cup vegetable oil
  • 1 teaspoon vanilla extract
  • 2 cups grated zucchini (no need to peel)
  • 1 cup coarsely chopped walnuts


  1. Grease and flour two 9-inch cake pans. Set aside.
  2. In a medium bowl, toss together the flour, baking powder, soda, salt, and cocoa. Set aside.
  3. In a large bowl, cream the butter and sugar, using an electric mixer. Beat until fluffy.
  4. One at a time, beat in the eggs. Then add the buttermilk, oil, and vanilla, beating after each addition until completely mixed.
  5. By thirds, beat in the dry ingredients. Then beat in the shredded zucchini, making sure it is completely incorporated into the batter.
  6. Stir in the chopped walnuts.
  7. Divide the batter equally between the prepared cake pans. Bake in the middle of an oven pre-heated to 350° F for 40-45 minutes or until a toothpick inserted in the center comes out clean.
  8. Remove the pans to a cooling rack for 5 minutes. Then run a thin metal spatula around the rims of the cake pans and turn out the cakes onto a rack to cool completely before frosting.
  9. When the cake is completely cooled, frost with the following seven-minute frosting.

Mocha Seven-Minute Frosting


  • ¾ cups sugar
  • ½ teaspoon cream of tartar
  • 1/8 teaspoon salt
  • 2 egg whites
  • ¼ cup cold water
  • 2 teaspoons vanilla extract
  • 1 tablespoon unsweetened cocoa
  • 1 tablespoon instant espresso coffee


  1. In a large stainless steel bowl or in the top of a stainless steel double boiler, whisk together the sugar, cream of tartar, salt, egg whites, and cold water.
  2. Place the bowl in a large pan or the bottom of the double boiler with simmering water adjusted so that the level of the water is at or above the level of the frosting mixture.
  3. With a hand-held electric mixer, beat for 5 to 7 minutes or until the temperature of the mixture reaches 140° F or the frosting stands in peaks.
  4. Remove from the water bath and continue to beat for 2 minutes more until the frosting stands in smooth peaks.
  5. Beat in the vanilla, cocoa, and coffee powder.
  6. Cool slightly and then frost the cake. There should be plenty for two 9-inch layers.
  7. If this “no-fail” does fail, you can “rescue” it by beating in ¼ -½ cup of confectioner’s sugar.


Filed under Food, Photography, Recipes


  1. Carol

    That looks delicious!

  2. Thank you, Carol. Being the master cake baker that you are, I think you would like it.

  3. As soon as I read this recipe, I knew it was one worth making. I just need an excuse to make a whole, gorgeous cake. I cannot believe how many years of work have gone into perfecting the cake and frosting. I love a classic cake recipe. 🙂

  4. I worked as a baker and actually ran my own bakery/restaurant for a while, Darryl , so when I tell you that you have every reason to be proud of this recipe!
    And you are right, the adjustment for high altitude/low altitude is to decrease the baking powder or soda in a recipe for higher altitude, lessen it for lower. Unless specified as high altitude, assume it’s for flatlanders! Yours is a perfect example of a “High Altitude” recipe/ I would also suggest increasing the soda to 1 1/2 tsp.
    You’ll laugh at this.Where I lived in Northern Virginia it was approximately 25 feet above sea level. A neighbor confided in me that she had been so green at cooking, she had been using high altitude adjustments to recipes when she lived in a 8th-floor apartment!
    [The only adjustment I’d make to yours is to tell you :next time, try an up-and-down motion on the sides when covering the cake with frosting.The top is fine.The sliced pieces look beautiful as they are anyway!]

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s