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horizontal image of Low FODMAP Blackout Cake on white plate

Low FODMAP Blackout Cake

If you are looking for a very chocolaty experience in cake form, that happens to be easy to make, this Low FODMAP Blackout Cake is the perfect choice. Moist cake with a rich pudding that you use for the filling and the frosting.

Course: Dessert
Cuisine: American
Prep Time: 20 minutes
Cook Time: 35 minutes
Total Time: 55 minutes
Makes: 20 Servings
Calories: 398 kcal
Author: Dédé Wilson





  1. For the Pudding: Place the cornstarch in a medium-sized saucepan. In a large measuring cup, combine the milk and cream. Drizzle a few tablespoons of the milk-cream mixture over the cornstarch and whisk until smooth. Pour the remaining milk-cream into the pan, then add sugar, chocolate, and salt. Cook over medium-low heat, whisking often, until the chocolate melts, then watch carefully as you bring it to a gentle boil. Whisk often as it thickens and takes on a pudding-like consistency; it should gently simmer for about 2 to 3 minutes. The pudding should be thick and glossy and leave whisk marks on top.

  2. Remove from the heat and whisk in the vanilla. Scrape into an airtight container; cool to warm room temperature. Press plastic wrap directly onto the surface, snap on the lid, and refrigerate for at least 6 hours or preferably overnight.
  3. For the Cake: Position a rack in the middle of the oven. Preheat the oven to 350° F (180°C).

  4. Coat two 8-inch by 2-inch (20 cm by 5 cm) round cake pans with nonstick spray, line the bottoms with parchment rounds, and then spray the parchment.
  5. Whisk together the flour, sugar, both cocoas, espresso powder, baking soda, and salt in a large bowl to aerate and combine. Whisk together the water, oil, vinegar, and vanilla in a medium bowl. Pour the wet ingredients over the dry mixture and whisk well until combined and very smooth. Divide the batter evenly between the two pans. Firmly tap the bottom of the pans on the work surface to dislodge any bubbles.
  6. Bake for 30 to 35 minutes, or until a toothpick inserted in the center shows a few moist crumbs when removed. Cool cakes in the pans on racks for about 10 minutes. Unmold, peel off the parchment, and place directly on the racks to cool completely. Trim the layers to be level, if necessary, reserving the scraps. The layers are ready to use. Alternatively, place the layers on same size cardboard rounds and double wrap in plastic wrap; store at room temperature and assemble within 24 hours.
  7. For the Assembly: Have all the components ready to use. Slice both cake layers evenly in half horizontally. Three layers will be used to assemble the cake. The fourth should be crumbled by hand into a bowl along with any scraps; this will be used for the exterior of the cake. Place one cake layer on a serving plate, bottom side down. Cover with a thick layer of pudding, top with the second cake layer and another layer of pudding. Top with the third cake layer, bottom side up. Cover the top and sides generously with pudding, which will be thick enough to stick to the cake. Use your fingers and palms to completely cover the cake top and sides with cake crumbs, pressing them into the pudding to adhere. Refrigerate for at least 2 hours and up to 2 days before serving slightly chilled.



  • Most cakes dry out in the fridge; the blackout cake doesn’t since it is filled and frosted with the pudding, which makes it a great do-ahead dessert for a birthday party or other celebration.
  • This is one of those cakes that looks impressive but is actually very easy. It’s always good to have that kind of cake in your repertoire.

FODMAP Information

Our recipes are based on Monash University and FODMAP Friendly science.

  • Chocolate: Monash University has lab tested dark, milk and white chocolate all have low FODMAP amounts: 85% dark at 20 g; dark at 30 g; milk at 20 g; white at 25 g.
  • Oil: All pure oils are fats and contain no carbohydrates, therefore they contain no FODMAPs.
  • Sugar: Monash University and FODMAP Friendly have both lab tested white, granulated sugar. Monash states that a Green Light low FODMAP serving size of white sugar is 1/4 cup (50 g). FODMAP Friendly simply states that they have tested 1 tablespoon and that it is low FODMAP. Regular granulated white sugar is sucrose, which is a disaccharide made up of equal parts glucose and fructose. Sucrose is broken down and absorbed efficiently in the small intestine.

Please always refer to the Monash University & FODMAP Friendly smartphone apps for the most up-to-date lab tested information. As always, your tolerance is what counts; please eat accordingly. The ultimate goal of the low FODMAP diet is to eat as broadly as possible, without triggering symptoms, for the healthiest microbiome.

Nutrition Facts
Low FODMAP Blackout Cake
Amount Per Serving
Calories 398 Calories from Fat 135
% Daily Value*
Fat 15g23%
Saturated Fat 3g15%
Sodium 257mg11%
Potassium 79mg2%
Carbohydrates 64g21%
Fiber 2g8%
Sugar 40g44%
Protein 4g8%
Calcium 9mg1%
Iron 2mg11%
* Percent Daily Values are based on a 2000 calorie diet.