Enjoy a star fruit dessert with a keto tropical version of an upside down cake. Baked with coconut flour and sliced star fruit, this star fruit dessert is also a gluten free cake to enjoy too. A taste of the tropics in a moist upside down cake.
Traditionally, an upside-down cake is make with pineapple, but we are in low carb terroritory here and pineapple has no place. However, star fruit makes a great low carb alternative to pineapple and looks pretty too in this keto upside down cake.
Is star fruit keto?
Star fruit is a great low carb tropical fruit with just 4g net carbohydrates per 100g serving. It is lower in carbs than berries too.
Sometimes known as Carambola, star fruit is a great low carb fruit and makes a change from berries. It has a high fibre content an and is great for potassium and vitamin C too.
As well as being a low carb garnish or addition to a keto fruit salad, star fruits make a pretty addition to an upside down cake.
What does star fruit taste like?
When the star fruit is yellow, it is at it’s ripest. It has a juicy, slightly sweet taste between a grape and a pear. Cooked, it does have a slight pineapple taste which makes it a great alternative to a pineapple upside down cake.
A green star fruit tastes a bit like an apple, but I personally prefer them ripe and sweeter.
Star Fruit Warning
However, a word of caution for those of you with kidney issues as star fruit has a high oxalate content, which is not good for the kidneys. They are also extremely toxic to dogs and cats too.
Keto Upside Down Cake Ingredients
For the low carb flour we used coconut flour, keeping the tropical theme of the cake.
The low carb sweetener you use may change the result in the topping due to crystallization once it is cold. It makes no difference in flavour but we would recommend allulose as that does not crystalize.
Spices could be added to the cake mixture that go well with the taste of star fruit. Try cinnamon, allspice or nutmeg.
How to make a star fruit upside-down cake
The star fruit must be ripe before you start slicing. The flesh should be firm but yellow in colour with a hint of green on the edges. If the edges are brown, don’t worry, it means that it is very ripe, and you just need to trim the edges.
- With a sharp knife trim the star fruit edges.
- Trim the top and bottom of the star fruit.
- Slice the star fruit.
- Toss the starfruit slices in the melted butter mixture.
The sliced star fruit is briefly sautéed in a buttery low carb sauce with lime.
Making the coconut flour cake
- Whisk the softened butter and allulose together until light and fluffy.
- Add the eggs one at a time and whisk.
- Add the remaining ingredients and whisk.
- If the batter is too thick add additional coconut milk.
- Place the star fruit slices in the bottom of the cake tin.
- Pour the cake batter over the star fruit and spread evenly. Bake.
I have previously added rum to this keto starfruit upside-down cake but that’s a matter of personal preference. My initial thoughts were that this would be a great cake for the Christmas season and a splash of rum would be part of the tropical flavor. I live in the Caribbean and rum cake is part of Christmas! However, I have not put this in the recipe and left it to you decide.
Frequently Asked Questions
Yes you can, but the quantity of almond flour will need to increase to 1 ½ cups.
Keep the cake in a sealed container in the refrigerator and it should last up to 4 days. The cooked star fruit helps to keep the cake moist.
More keto star fruit recipes
This recipe was originally posted in December 2019. The photos and content have been updated.
This post may contain affiliate links. Please read my disclosure policy for more information.
Upside Down Star Fruit Cake
- 1 star fruit
- 2 tablespoons unsalted butter
- 2 tablespoons allulose or other low carb sweetener
- 1 tablespoon lime juice
- Preheat oven to 180C/375F degrees
- Grease an 8 inch spring form cake tin. Line the bottom with parchment paper
- Thinly slice the star fruit to about 1 cm in width
- In a small bowl, melt the butter in the microwave for 30 seconds and add the allulose and lime juice.
- Dip the sliced star fruit slices into the melted butter mixture.
- Place the star fruit slices on the bottom of the cake pan.
MAKE THE CAKE
- In a large bowl, beat the allulose and butter together until light and fluffy.
- Add the vanilla extract and eggs, one at a time and whisk well.
- Add the coconut flour, salt and baking powder and continue to whisk.
- Gradually add the coconut milk until you have a smooth batter.
- Pour the cake batter into the star fruit lined baking pan.
- Bake for 30 -35 minutes until the cake is firm and golden. Check that it is cooked through with a toothpick.
- Remove from the oven and let cool in the tin for at least 10 minutes.
- Run a spatula around the outside edges of the cake to loosen it.
- Place a plate over the cake tin and carefully turn it upside down.
- Allow the cake to sit on the plate and remove the cake tin.
- Cool the cake at room temperature before serving.
YOUR OWN NOTES