Episode 5, GBBO 2015, Signature Bake

Sugar-Free Cake

This was the signature challenge on Free-From Week (otherwise known as Alternative Ingredients Week) in the 2015 season of the Great British Baking Show. The judges were pretty clear that they didn’t want the bakers to use anything that would come in a bag (like Splenda or Stevia) but were looking for syrups like agave, honey or maple syrup. So I would consider it a “no refined sugars” challenge.

When I googled “sugar-free cake” I found mostly recipes that called for erythritol, Splenda or other processed sugar substitutes. When I searched for “making cake with liquid sweeteners” I found this great article on the King Arthur Baking Co. website explaining how to bake with honey, maple syrup or molasses and how to substitute them for regular sugar in recipes. (HINT: It’s not necessarily one-for-one, and you have to adjust the recipe to account for the extra liquid.)

As an example, they used this recipe for an oil-based chocolate cake to demonstrate how to substitute honey for sugar. This Cake Pan Cake was named King Arthur Baking Company’s 225th Anniversary Recipe of the Centuries and 2014 Recipe of the Year. It is unique in that it uses neither eggs nor butter, and milk is optional! You don’t even need an electric mixer (although it helps to use one for the frosting). It’s a simple, one-bowl mixture and can even be mixed right in the pan that it’s baked in — thus the name!

This chocolate cake embodies the ingenuity of home bakers who, in the hard times of the Great Depression and during the rationing of World War II, made the most of what they had. Back when butter and eggs were scarce — and expensive — thrifty housewives learned to bake with oil instead of butter and water (or coffee) instead of milk. And a combination of baking soda and vinegar (a base and an acid) created a chemical reaction that would cause the cake to rise just as if it had eggs in it.

Similarly, learning to bake with what’s readily available may involve switching up sweeteners. Honey, maple syrup and molasses may have been available to bakers in the Great Depression when refined sugar was not. They would have had to know how to adapt a recipe based on how sweet the substitute is compared to sugar and how much to reduce the liquid or increase the flour in a recipe to compensate for the liquid sweetener.

Fortunately, I had King Arthur Baking Company to do that for me. Because honey is sweeter than sugar, I only needed three-quarters of the volume of honey than the sugar in the recipe. I also reduced the liquid the recipe called for by 3-4 tablespoons per cup. Using a liquid sweetener instead of sugar results in a moister, softer cake, and honey softens the chocolate flavor, giving it a mellow, slightly earthy aroma.

I paired the chocolate cake with a peanut butter frosting sweetened with maple syrup. It’s easier to experiment with frosting recipes than cake recipes, so I started with half a cup of natural peanut butter (the kind without added sugar) and half a cup of mascarpone cheese, whipped together with one-quarter cup of maple syrup. Then I kept tasting and adding until I came up with the flavor and consistency I was looking for. The resulting frosting was creamy and peanut-buttery, not too sweet but with a slight maple-y flavor. It was a perfect partner for the chocolate cake, especially for anyone who (like me) loves Reese’s Peanut Butter Cups (or anything combining chocolate and peanut butter, for that matter). 

Because peanut butter goes well with chocolate AND honey, it was a natural combination. And because the other flavor that goes really well with chocolate and peanut butter is banana, I added a few banana slices to the top for decoration.

I think I can safely say that everyone who had a piece of this cake loved it. In fact, it has turned out to be my family’s favorite of all the cakes I’ve made for them so far. It was moist and tender with a perfectly soft crumb. It did not last long, but I think it’s one recipe that I will return to again and again.

(Refined) Sugar-Free Chocolate Cake with Peanut Butter Frosting

Cake recipe adapted from KingArthurBaking.com

For the cake:

  • 3 c. unbleached flour
  • ½ c. Dutch-process cocoa powder
  • 1 t. salt
  • 2 t. baking soda
  • 1½ c. honey
  • 2 t. vanilla
  • 2 T. vinegar
  • 2/3 c. vegetable oil
  • 2 c. less 5 T. milk

For the frosting and decoration:

  • 1 c. creamy peanut butter (natural, no sugar)
  • 1 c. mascarpone cheese
  • 1 t. vanilla
  • ¼ t. salt
  • 7 T. maple syrup (or to taste)
  • 1 banana, sliced, for topping (opt.)


  1. Preheat oven to 350°F. Lightly grease the bottom of two 9-inch round cake pans and line with parchment. (TIP: To ensure a flat-topped cake, wrap pans with moistened insulated baking strips or wet paper towels covered with aluminum foil.)
  2. In a medium bowl, whisk together flour, cocoa powder, salt and baking soda. In a separate bowl or large measuring pitcher, whisk together honey, vanilla, vinegar, vegetable oil and milk. Pour wet ingredients into the bowl of dry ingredients and stir until thoroughly combined. Divide batter evenly between the prepared pans.
  3. Bake for 30-35 minutes, until a toothpick inserted in the center of the cake comes out clean and the surface of the cake bounces back when gently poked. Let cake cool in pans for 10 minutes, then release onto cooling racks. Cool completely before frosting.
  4. To make the frosting, use an electric mixer to beat the peanut butter, mascarpone, vanilla and salt together. Mix in ¼ cup (4 tablespoons) maple syrup. Add more maple syrup, 1 tablespoon at a time, to taste.
  5. Place the bottom cake layer on a platter. Spread one-third of the frosting on top of the bottom layer. Place the other cake layer on top and spread another third of the frosting on top of it. Transfer the rest of the frosting to a piping bag fitted with a star tip. Pipe 12 rosettes around the top of the cake. Insert a banana slice into each rosette, and pile a few more slices in the center of the cake. Refrigerate until ready to serve.
Up next: Gluten-Free Pita (or Pitta) Bread

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