Easy Keto Blueberry Mug Cake - Ready in 1 Minute

This keto blueberry mug cake recipe is a fluffy single serve cake that cooks in just one minute. It is perfect for those times when you want a simple and quick dessert.

Do you know that time in the afternoon when you sit down with a cup of tea or coffee and think - wouldn't it be nice to have a sweet treat now?

Well, that's exactly where this gluten free, sugar free mug cake comes in. It's a variation on my vanilla mug cake, which I customised by adding a super fruity blueberry centre.

It tastes like keto blueberry muffins, but in a mug - a keto blueberry mug muffin!

What is a mug cake?

In case you've never made a mug cake before, let me explain: A mug cake is a single serve cake in a mug, cup or ramekin. It requires only a few minutes prep and cooks in the microwave.

Using an egg and baking powder makes a microwave cake rise and become fluffy.

Are blueberries keto friendly?

Blueberries are a good choice of fruit when you're on a keto diet. Berries are low in net carbs, bursting with antioxidants and contain high amounts of vitamin C and fiber.

Read this article to find out all about the health benefits of blueberries!

Ingredients

You only need 8 simple ingredients to make this low carb mug cake. Here they are:

• Almond Flour - Both ground almonds and super fine almond flour work well.
• Coconut Flour - You need this nut free, gluten-free flour for extra stability.
• Butter - Substitute with coconut oil for a dairy free version.
• Egg - Use a medium egg if using regular almond flour and a large egg if your almond flour is super fine.
• Sweetener - I used a granulated erythritol monk fruit sweetener blend. However, you can use allulose, xylitol, Bocha Sweet, Swerve or pure erythritol.
• Vanilla extract (or use 1 teaspoon lemon juice and lemon zest!)
• Baking powder - Make sure it is fresh.
• Blueberries - I used 10 fresh berries.

It's important to level the tops of all tablespoons when measuring.

My top tip

I like to dust my blueberries in coconut flour before adding them to the batter. Coconut flour is very absorbent and it prevents the blueberries from sinking to the bottom of the mug.

I pressed my blueberries into the middle of the cake, because I wanted to create a soft blueberry centre.

You can also stir them into the batter like you would for a blueberry muffin.

How to make a keto blueberry mug cake

(This section contains step by step instructions and photos that show how to make this recipe. Find the recipe card with ingredient amounts and nutritional information at the bottom of the post.)

1. Stir together the dry ingredients in a small bowl - almond flour, coconut flour, baking powder, sweetener. Take care to break up any lumps. 

2. In a second bowl, whisk the egg. Then add the melted butter plus the vanilla extract and whisk all wet ingredients until combined.

3. Now, add the dry ingredients to the wet and stir until a smooth batter forms. 

4. Grease a mug or ramekin with butter and fill in the batter. Press the blueberries into the centre, leaving a little gap at the top. Microwave for 80 seconds at 900 watts.

Serving suggestions

Depending on whether you want to impress or not, enjoy the microwave cake straight from the mug or invert it onto a plate.

Here are some topping ideas:

• Dust with powdered sugar
• Add a dollop of whipped cream
• Add a spoonful of sugar free blueberry jam
• make a low carb cream cheese frosting

Microwave timings

I have a 900 watt microwave and my cake took 80 seconds to cook. Here's a quick overview of recommended baking times for this mug cake recipe: 

• 600W = low power. 100 seconds. 
• 800W = 90 seconds.
• 900W = 80 seconds. 
• 1000W = 70 seconds
• 1200W = 60 seconds. 

After these times, check whether the cake is done. If it's still undercooked, add increments of 10 seconds. 

FAQs

Can I make it in the oven?

Yes, you can! Preheat the oven to 180C / 350F electric or 160C / 320F fan assisted. Bake for 12-15 minutes or until a skewer or toothpick inserted comes out clean with no crumbs sticking.

It should also be possible to cook this keto mug muffin in an air fryer. For this, I would choose a temperature of 160C / 320F and check for doneness after 10 minutes.

Which mug to use

If you fill the cup or ramekin to the top with batter, it will overflow and create a mess. Therefore, choose a cup that holds a minimum of 200ml.

You want to have at least 2 fingers of space at the top so the cake can rise.

Can I use frozen berries?

Yes, it's possible to make this keto blueberry mug cake with frozen blueberries. Rinse and pat the berries dry, then proceed as per recipe.

Can I use other berries?

Of course! You could use raspberries, blackberries or even cubed strawberries.

And if you feel like something different, use sugar free chocolate chips!

Nut free variation

For a coconut flour version, omit the almond flour and use 1 ⅔ cups of coconut flour instead.

Vegan option

Replace the egg with a flax egg made from 1 tablespoon flax and 2.5 tablespoons almond milk.

Storage

Mug cakes are best eaten straight away. They have a tendency to turn dense if left for a couple of hours.

More keto mug cake recipes

Here are some more of my microwave cake recipes. I can't decide which one I like best!

Tried this recipe? Give it a star rating below!

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