Sonja Kramar

Gluten-Free Plum and Walnut Cake

A simple plum and walnut cake made without added sugar, eggs or butter. The batter contains just a few basic ingredients and comes together quickly, making this a perfect recipe for plum season or for using frozen fruit.

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Prep Time 15 minutes mins

Cook Time 30 minutes mins

Total Time 45 minutes mins

Ingredients  

• 100 g whole-grain oat flour
• 60 g ground walnuts
• 150 g unsweetened applesauce
• ½ teaspoon baking soda
• 400-500 g plums

Instructions

 

Preheat the Oven

1. Preheat the oven to 180°C.

Prepare the Batter

1. In a bowl, combine the oat flour (or another flour of your choice), ground walnuts, applesauce and baking soda. Mix until evenly combined.

Add the Plums

1. Spread the batter evenly in a 16 cm round cake pan. Cut the plums in half, remove the pits and slice them into wedges. Arrange them closely together over the batter.

Bake the Cake

1. Bake for approximately 30 minutes, or until the edges are golden brown and the plums have softened.

Cool and Serve

1. Allow the cake to cool slightly before slicing. It is delicious served while still slightly warm, but it also keeps well until the following day.
Serving suggestion: Serve the cake slightly warm, either on its own or with a spoonful of thick plain or plant-based yogurt.

Notes

• For this recipe, I recommend using actual oat flour rather than ground rolled oats. You can read more about this in the tips below the recipe.
• Frozen plums can also be used in this recipe. There is no need to thaw them before baking.

Why I use oat flour in this recipe

This is one of the first recipes I ever developed for Brezgrešne sladice, my Slovenian website. Back then I used whole grain oat flour in most of my baking because I loved its nutrition and its mild, slightly nutty flavor. I’d probably do a few things differently today, but I’ve left the recipe as it was because it still works beautifully.

One thing matters here, though: use real oat flour. I often get asked if you can just blend rolled oats into flour at home. In my experience, I wouldn’t. Rolled oats have already been heat-treated and soak up much more liquid than oat flour, so the batter turns out heavier, denser and sometimes a little gummy.

No oat flour? You can swap in whole grain spelt flour, kamut flour or buckwheat flour. Each one gives the cake a slightly different flavor, and all of them taste great. (New to kamut? Here’s my guide to kamut flour.)

Over the years of developing recipes and learning about gluten-free baking, I tried lots of flour combinations. That’s how I ended up creating my own gluten-free flour blend, which I use in most of my newer recipes. It gives a lighter texture and more predictable results with fruit desserts. This plum cake stays true to its original version, though: simple, four basic ingredients, and it still works every time.

Can I use a different fruit instead of plums?

Absolutely. This batter isn’t just for plums. You can use it with other seasonal fruit, so the cake works all year round.

It’s especially good with:

• apples,
• pears,
• apricots,
• peaches,
• nectarines,
• sour cherries or sweet cherries.

You can use frozen plums, too, and there’s no need to thaw them first. Just arrange them over the batter and bake the cake a few minutes longer if needed.

Because the batter itself isn’t very sweet, I recommend ripe, flavorful fruit. That way the cake is naturally sweet without any added sugar.

How to store plum and walnut cake

This cake is best on the day you bake it, while it’s still a little warm, but it keeps well for a few days.

You can:

• keep it at room temperature for up to 2 days, well covered so it doesn’t dry out,
• store it in the fridge in an airtight container for up to 4 days,
• freeze it in individual slices. Thaw them at room temperature or warm them briefly in the oven before serving.

If you serve it slightly warm, it turns soft again and the walnuts taste even better.

Plum and walnut cake FAQ

Can I use frozen plums?

Yes. Use them straight from the freezer, no thawing needed. Arrange them over the batter and bake the cake a few minutes longer if needed.

What can I use instead of oat flour?

You can use whole grain spelt flour, kamut flour or buckwheat flour. Each one gives the cake a slightly different flavor and texture, but the recipe still works well.

Can I make the cake without walnuts?

The walnuts add both flavor and texture, so I wouldn’t just leave them out. If you don’t want to use walnuts, try the same amount of ground almonds or hazelnuts instead.

How do I know when the cake is done?

The cake is ready when the edges are golden brown and the center feels firm when you touch it. A toothpick inserted in the middle should come out without any wet batter.

How long does the cake stay fresh?

About 2 days at room temperature, or up to 4 days in the fridge. Warm it up briefly before serving if you like.

Is this plum and walnut cake gluten-free?

It can be, but only if you use certified gluten-free oat flour or another reliable gluten-free flour blend. Regular oat flour is often cross-contaminated with gluten, so it isn’t safe for people with celiac disease.

These days I usually bake gluten-free with my own flour blend. I developed it over years of recipe testing, because a well-balanced blend gives more reliable results and a nicer texture than a single gluten-free flour.

Can I use homemade applesauce?

Of course. Homemade applesauce without added sugar works great here. Just make sure it isn’t too runny. If you don’t have any yet, you can check out my homemade applesauce (in Slovenian for now).