Here’s my trick: I replaced some of the berries in this Keto Raspberry Dumpcake with rhubarb to thicken the filling without starch or gums while keeping the carbs low.

(c) 2021, Keto Raspberry Dumpcake

Thickening recipes without starch is a challenge; I came up with a new way to do it without adding carbs or altering the taste of the fruit in this jammy, crunchy dessert. If you don’t tell anyone what is in it, they will never guess. (Here’s my trick: I replaced some of the berries in this Keto Raspberry Dumpcake with rhubarb to thicken the filling without starch or gums while keeping the carbs low.)


  • 1¾ cups (8 ounces) of frozen raspberries, blackberries, or strawberries (sliced if large)
  • 3 tablespoons low-carb sweetener with bulk, such as Lakanto Monk Fruit, Wondrose, Swerve, or other blend (without Allulose!)*
  • 3 tablespoons of a second sugar-free sweetener, such as liquid monk fruit, stevia, or sucralose (Using a second sweetener will minimize the crystallization of the erythritol in the cake.)
  • 1½ cups (6.6 ounces) chopped, fresh or frozen rhubarb **See Notes below about which kind to use and how to prepare it.
  • One box of sugar-free, low-carb vanilla or chocolate cake mix that makes one 8-inch layer*** (I used Keto and Co Vanilla Cake Mix, which has the lowest carb count that I could find.)
  • ¼ cup sliced almonds, optional
  • ½ teaspoon True or Ceylon cinnamon (preferably not Cassia), optional
  • ¾ cup cold sustainable palm shortening (for dairy-free) or chilled butter or ghee


Grease bottom and sides of an 8- x 8-inch cake pan. Sprinkle 1½ teaspoons of the dry cake mix or a little almond flour over the bottom of the pan.

To make fruit filling:

Thaw frozen berries in a strainer set over a container to catch the juice. Add a little water to the liquid if necessary to make about ½ cup. Reserve both berries and liquid.

Thaw and drain chopped rhubarb, if frozen. Discard any liquid from rhubarb, if frozen. Place rhubarb in a saucepan with the ½ cup of juice drained from the raspberries. Add the sweeteners. Stir and simmer over low heat until reduced to a thick paste, about 20 minutes. Add reserved raspberries and continue to cook for about 5 minutes more. Let cool. Spread filling in bottom of greased pan.

To make the Raspberry Dump Cake:

Ignore the directions on the cake mix box. Pour the dry cake mix over the raspberry/rhubarb filling and spread with your fingers, breaking up any lumps. Sprinkle cinnamon and sliced almonds over the top, if using.

Scoop up bits of cold shortening with a teaspoon and drop evenly over the cake mix or slice chilled butter and scatter over cake mix. 

Bake cake at 350º F for about 45 minutes or until it is bubbly and brown. When it is done, the juices should have cooked down so they are thick and gooey and the crust should be crunchy on top. Poke the top all over with a fork to break into rough crumbles.

Serve warm with sugar-free ice cream or whipped cream, if desired.

Serving: 12 servings

Nutrition Data for each of 12 servings:
Calories: 163; Fat: 13.9g; Carbs: 23.4g; Fiber 11.1g; Sugar Alcohol: 7.4g; Net Carbs: 4.9g; Protein: 1.2g; RAE (Retinol Activity Equivalent): 2.11 mcgs (or less if rhubarb is peeled.)

Nutrition Data is for Berry Dump Cake if made with raspberries and rhubarb and a box of Keto and CO’s Vanilla Cake Mix. Other cake mixes may vary in nutrition counts, but Keto and Co’s mix is one of the lowest in carbs that I have found. (Be sure to add only the nutrition amounts in the dry mix, not the whole recipe, if you use a different brand.)

Optional ingredients and sweeteners are not included in counts. Most of the keto sweeteners have little to no effect.


“Dump Cake” is the name given to recipes that don’t require stirring. You just dump everything in a pan and bake it. The fast and dirty version of this raspberry dump cake would have just three ingredients: a can of pie filling, a box of cake mix, and butter. My clean version calls for a few more, but it is still quick and easy.

Sugar-free cake mixes:

***Use a sugar-free, almond flour-based cake mix that makes one 8-inch layer. Don’t use one that contains regular wheat flour even if it is “sugar-free.”(It will work, but the nutrition data will not be acceptable.) Swerve Sweets, Keto and Co Vanilla Cake Mix, Zen Sweet, Thrive’s Switch, and other brands are available with slightly different nutrition data. They all call for eggs and oil, but since you will only be using the dry ingredients, those don’t matter. I used the Keto and Co’s mix shown below to calculate the nutrition data, but I have also made the recipe using the ones from Swerve, Zen Sweets, and Thrive:

*** Berries:

I used raspberries for my berry dump cake because they are low in carbs and work well when paired with rhubarb. Strawberries and rhubarb are the classic combination, but other berries are equally nice. I want to try marionberries or blackberries next.

*** Rhubarb:

Rhubarb is mostly fiber. It cooks down to a smooth paste, perfect for thickening pie and cake fillings or making jam. (The filling for this raspberry dump cake makes a fantastic, low-carb jam when used on its own!)

Most of the rhubarb sold in grocery stores is bright, metallic red. People tend to prefer it because it is so pretty. The variety that grows best here in the Northwest is pale green with a pink blush toward the bottom of the stalks. In either case, the color is just a thin layer on the outside of the stalks; they are all white on the inside and the color is not an indication of sweetness or flavor. I think my homegrown rhubarb is lovely and it tastes wonderful. Since I still have six months of detoxing left from an overdose of vitamin A (from too much liver, a retin-A skin cream, and vitamin A supplements, I assumed that my pale, homegrown rhubarb would be safer for me than the screaming red variety found at the grocery stores. (Vitamin A is red, orange, or yellow and may also be hidden in dark green foods.) I ran the nutrition counts on several different databases and they showed a range of vitamin A content from less than 2% to 20% of the RDI in 100 grams! The paler varieties must surely be lowest, but none of the data bases differentiate by variety. You can reduce them all to zero, however, by using a vegetable peeler to remove the colored, outer layer.

One possible caveat about eating a lot of rhubarb, especially if you are prone to gout or kidney or gall stones: it is very high in oxalates. Old stalks will have more oxalates because they migrate down from the leaves over time. (And NEVER eat the leaves!)  

Read more about rhubarb at: Rhubarb: Nutrition, Benefits, and More (

About Allulose:

Some new sugar substitute blends contain Allulose, “King Arthur’s Baking Sugar Alternative,” for example, lists Allulose as the third ingredient. I don’t recommend any of them for this recipe. Even a few tablespoons of Allulose will prevent the cake from getting crusty on top. The texture will also be different and it will brown too fast. The King Authur Flour company offers several suggestions for dealing with over-browning, such as: “tent with foil if it occurs, lower temperature by 25 degrees, test when baked item is two-thirds done,” etc. They also have advice about how to substitute it for regular, powdered, or brown sugar, but it is in a paragraph that bears the ominous heading, “Manage Your Expectations.” The web site,, includes some recipes, so it is probably best to stick with those and use other blends for baked goods until you are experienced with it. Allulose excels as an ingredient in sauces, drinks, puddings, frostings, ice creams, candies, and other foods where smoothness, moistness, and softness are desired, but doesn’t adapt as well for baking.


I am not a doctor and cannot give medical advice. If you believe you have a health problem, consult a medical practitioner.

I am not an affiliate of any company and do not receive a commission on product sales.

(c) 2021, Judy Barnes Baker

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Judy Barnes Baker

The working title for my first book was, “You’ll Never Know What You Are Missing.” It summed up my goal: to make eating for health synonymous with eating for pleasure. Once you discover the secret, you will find that the very best food for weight management, longevity, the treatment and prevention of disease, and over-all health and happiness is also the most sumptuous, satisfying, and indulgent way of eating the world has to offer. You are invited to the feast. Enjoy!
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Andrea Tiktin-Fanti
Andrea Tiktin-Fanti
2 years ago

As with all of your recipes, this sounds delicious. I cannot wait to try it. Reading your posts is like taking a college course. Thank you so much for all of the hard work you do to come up with these things.

Justin Marchert
Justin Marchert
2 years ago

Delicious! Loved this desert, as did the family. And so easy. Kudos. 🙂

1 year ago

Hey, Judy. Jude in Canada here. I have pretty much every LC product known to humankind (and most books including yours) but no ready Cake Mix. Can you recommend one of your cake recipes (minus any liquids such as eggs, oil) that I can assemble and use instead? Essentially, a JBB Cake Mix? Thanks so much.