Keto Lemon Mug Cake (Low-Carb Single-Serving Dessert)

This Keto Lemon Mug Cake is what I make when I want something sweet without a whole cake sitting in the fridge tempting me for a week. Bright lemon flavor, a tender crumb, and about five minutes total between mixing and eating.

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I’m the only one doing keto in my house, so a full dessert recipe usually means days of leftovers I don’t need around. A mug cake solves that problem entirely, one serving, a handful of common ingredients, and done before the microwave timer even feels long.

Use a mug much bigger than the batter looks like it needs. It roughly doubles in size as it cooks.

Chef Jenn’s Take on Keto Lemon Mug Cake

Keto desserts can be genuinely frustrating to navigate. A lot of packaged “keto” treats turn out not to be very keto at all once you actually read the nutrition label, and full-size cake recipes leave you with days of something tempting sitting in the fridge if you’re the only one in the house eating that way.

Not overmixing the batter is what keeps this from turning dense or rubbery. A few small lumps are fine, and pushing past that point is the most common way a mug cake goes wrong. For more single-serving keto desserts like this one, check out my Desserts collection.

What You’ll Love About Keto Lemon Mug Cake

• It’s portioned for one, so there’s no extra cake sitting in the fridge tempting you for days after you only wanted a bite.
• It’s ready in about five minutes total, which matters on the nights a real craving hits and waiting isn’t an option.
• The bright lemon flavor makes it feel like a genuinely different treat from the usual chocolate mug cake rotation.

Ingredients

• Almond flour – Super-fine grind gives the best texture if you can find it.
• Coconut flour
• Baking powder
• Butter – Salted works well. Add a small pinch of salt if using unsalted.
• Egg – Just one.
• Brown sugar substitute – Use your favorite brand.
• Lemon juice – Freshly squeezed.
• Lemon zest

How To Make The Best Keto Lemon Mug Cake

Scroll down for the full recipe card with exact measurements and printable instructions.

Mix the almond flour, coconut flour, and baking powder together in a small bowl.

In a separate bowl, mix the melted butter, egg, sweetener, lemon juice, and lemon zest until combined.

Combine the wet and dry ingredients, stirring just until mixed. A few small lumps are fine, don’t overmix. Butter the inside of a large mug, well beyond the size the batter looks like it needs, then pour in the batter.

Microwave on high for about 90 seconds. Check for doneness with a toothpick, a few moist crumbs are fine, but no raw batter. Give it another 10 to 15 seconds if needed.

Make It A Meal

This one’s a single-serving dessert, so I usually pair it with a cup of coffee or tea rather than a full meal. If you want more single-serving keto desserts in the rotation, Raspberry Cheesecake Bites make a good no-fuss option for another night. For an occasion that calls for something bigger, Basic New York Cheesecake or Low-Carb Blueberry Lemon Cake both make good options when you’re serving more than just yourself.

Storage

Store leftover mug cake in an airtight container in the fridge for 2 to 3 days. Warm gently in the microwave before eating again.

FREQUENTLY ASKED QUESTIONS

WANT EVEN MORE EASY KETO DIET RECIPES?

I’m always in the kitchen creating new recipes, and while some of them are big hits, I get some misses, too. But these are some of my favorite all-time recipes:

• Thick and luscious Salmon Chowder
• Grilled veggies – I love how versatile this recipe is!
• This amazing cauliflower dish
• Meaty sausage Parmigiana