Easy Keto Nut Free Low Carb Sugar Free Lemon Mug Cake
This easy keto Sugar Free Lemon Mug Cake is low carb, nut free, gluten free, and a single serving for perfect portion control! Just 3 grams net carbs!
Easy Keto Lemon Mug Cake
There is just something about tangy lemon flavor that feels like hope in dessert form. Bright. Fresh. Clean. Even in the dead of winter here in New England, the smell of lemon instantly reminds me that spring will come again.
This Sugar-Free Lemon Mug Cake is one of those recipes I keep coming back to year after year, (first published in March 2015)—especially when I want a single serving sweet treat without leftovers calling my name from the counter.
It’s also one of the easiest recipes the next time you are craving a lemon dessert!
It’s:
- Low carb and keto diet friendly
- Gluten free, grain free, and nut free
- Made with coconut flour (not almond flour)
- A true single serving with built-in perfect portion control
- Just 3 net carbs per serving
It’s the easiest way to satisfy a sweet tooth without blowing your goals.
Why Lemon Has Always Been My Go-To
I’m a lemon lover—always have been.
Lemon in my water, lemon in my seltzer and in lemon recipes as much as possible.
Sugar-Free Frozen Lemonade, this Strawberry Lemon Sorbet, and these delicious No Bake Lemon Cheesecake bars have been reader favorites for years.
But lemon is also personal for me.
When my throat feels scratchy or sore, I’ve literally taken the juice of an entire lemon as a quick shot. It might sound intense, but it works better for me than anything else I’ve tried. Lemon has always symbolized healing, freshness, and getting back on track—especially during cold, snowy months.
This mug cake was born out of that same mindset: something comforting, simple, and supportive.
The Testing Behind This Recipe
Before this recipe ever went live, I tested it four different times.
- Coconut flour only
- Coconut flour with flaxseed
- One egg vs two eggs
- More lemon juice vs less lemon juice
I was looking for fluffy texture, not rubbery. Moist, not dry. Lemon-forward but not overpowering.
This version is the winner.
Even if you think you don’t like coconut—trust me—the coconut flavor is not noticeable here. The lemon is the star. My youngest, who hates coconut in every form, absolutely loved this.
Sugar-Free Lemon Mug Cake Ingredients
Dry Ingredients
- Coconut flour
- Baking powder
- Pinch of salt
Wet Ingredients
- Egg
- Fresh lemon juice
- Heavy cream (or coconut cream)
- Lemon liquid stevia
Using coconut flour is essential here. Almond flour cannot be swapped evenly—the texture will not work.
Coconut Flour & Allergies: Let’s Clear This Up
I get this question almost daily.
Is coconut a tree nut?
Botanically speaking, coconut is actually a fruit (a drupe, like a peach with a pit). While the FDA classifies coconut as a tree nut for labeling purposes, it is not a botanical nut.
My own son was diagnosed with a peanut and tree nut allergy at age two. He has safely eaten coconut for years without issue.
That said, if you have allergies, always check with your allergist.
The American College of Allergy, Asthma & Immunology explains that while coconut reactions are possible, most people with tree nut allergies tolerate coconut just fine.
Why This Is the Perfect Mug Cake
This is one of those low carb mug cakes that actually works:
- Uses a microwave-safe mug or small ramekin
- No fancy equipment
- No leftover cake sitting on the counter
- Ready in about 1 minute of cooking time
It’s ideal for anyone following a low-carb lifestyle, ketogenic diet, or anyone simply wanting better portion control.
Easy Lemon Mug Cake Frequently Asked Questions
Can I make this dairy free?
Yes. Swap the heavy cream for canned coconut cream.
Can I use a different low-carb sweetener?
Absolutely. Use any low-carb sweetener you prefer. If you need help adjusting amounts, my Sweetener Guide & Conversion Chart makes it easy.
What size ramekin should I use?
A 7-ounce ramekin works best. You can also divide the batter into two smaller ramekins for 2 single servings of this sugar-free mug cake.
Can I bake this instead of microwaving?
Yes.
- Preheat oven to 350°F
- Bake for 10 minutes or until a toothpick comes out clean
What’s the frosting shown in the video?
That’s my sugar-free vanilla buttercream frosting—totally optional but delicious.
Why I Still Love This Recipe Years Later
This recipe may be simple, but it represents everything I believe in now more than ever:
- No all-or-nothing thinking
- No white-knuckling through cravings
- Simple recipes that support long-term health
Sometimes the best dessert is the one that lets you enjoy a few bites and move on—satisfied, not spiraling.
And if you’re someone who loves lemon as much as I do, this one never disappoints.
More Keto Mug Cake Recipes
More Sugar Free Lemon Recipes: Lemon Cheesecake Mousse, Lemon Custard Pie, Crock Pot Lemon Blueberry Cake.
Other Low Carb Recipes You Might Like:
- 1 Minute Sugar Free Chocolate Mug Cake
- Pumpkin Chocolate Chip Mug Cake
- Red Velvet Couples Mug Cake
- Carrot Cake Mug Cake
Need help meal planning? My weekly Midlife Macro Meal Plans are available each week using all my recipes for low-carb meals, and snacks.
If you’re following a classic keto diet, this meal plan works for both low carb, midlife and classic keto approaches, sent directly to your inbox. Easy meals each night of the week! Shopping list is done for you! Want a sample plan?
Sugar-Free Lemon Mug Cake
Ingredients
- 1 egg
- 2 tablespoons lemon juice and lemon zest optional
- 2 tablespoons heavy cream
- 1/2 teaspoon lemon liquid stevia or 1/4 cup low carb granular sweetener
- 2 tbsp coconut flour
- 1/4 teaspoon baking powder
- pinch salt
Instructions
- Whisk the egg, lemon juice, cream and stevia together in a small bowl.
- Stir in the coconut flour, baking powder and salt.
- Pour batter evenly into two 7 ounce ramekins or or 1 microwave-safe mug or bowl.
- Microwave 1 minute then in 30 second intervals for each lemon cake or until toothpick in center comes out clean.
- Top with sugar free whipped cream if desired!
Oven instructions
- Preheat your oven to 350 degrees F. Bake for 10 minutes or until a toothpick in center comes out clean.
Video
Notes
Nutrition
About Brenda
Brenda Bennett is a certified Nutritional Therapy Practitioner, certified Sugar Detox Coach, certified Keto Coach, and certified Life Coach. She has been Sugar Free & refined-carb free for 20 years and is the author of four cookbooks: Sugar-Free Mom, Naturally Keto, The 30-Day Sugar Elimination Diet, and her newest release, Good, Better, Best (2025). Her work focuses on helping women detox from sugar, eliminate cravings, balance blood sugar, and lose weight while enjoying delicious, nutrient-dense whole foods. Brenda is also the creator of the Midlife Macro™ Method and the weekly Midlife Macro Meal Plans™, designed specifically for women in perimenopause and menopause who want simple, high-protein, low-carb meals to support hormones, metabolism, and long-term health.She is the founder of the Sugar Free Fresh Start course and the Sugar Free Mom Tribe membership.
I *have* to make this Today. I don’t have a microwave. How long would I bake it in a 350(?) oven?
I would guess just 15 minutes then check in center with a toothpick.
I’m so glad Monica asked ..and you answered.. I’m so wanting to try this (and will tonight), but I don’t use my microwave. Aafter seeing a demonstration of two plants, treated exactly the same except one was watered with tap water and the other with microwaved (then cooled, of course) water. Will never forget the picture of that poor plant that got the microwaved water. So, now I can very happily make this as suggested, in the oven.
Don’t have any heavy cream on hand right now, anything else I could use?
I’m sure it would still be tasty using milk or even coconut cream from the can.
This looks heavenly what if I don’t have liquid lemon stevia?
Use any sweetener you like.
Is there any way to make this in larger version?
I’m making this now!
Delicious!! Short list of ingredients = my kind of recipe 😉 I’m thinking breakfast tomorrow morning!! I love that you can use coconut cream instead of regular cream.
I am a serious lemon lover so this one is right up my alley. I think it’s that time of year where we’re so over winter, all of us are craving citrus, hoping it jump starts spring. I can’t wait for sunshine.
There is nothing more cheery than lemon in everything at the end of a long winter. I’ve never made a mug cake before, but this one looks divine!
the prettiest mug cake i have ever laid eyes on!
I am definitely a lemon lover! And you can’t beat 4 minutes with a dessert!
I’m so over winter and am more than ready for all things lemon! This cake looks really tasty. I think I’ll ty it for dessert tonight!
I just had to make this right away after I saw this recipe. Love anything lemon. So disappointed that I did not have any coconut flour left after I had the other ingredients, so I used spelt flour and it turned out great. I liked it a lot. Since I never made it with coconut flour, I cannot vouch for that. But will definitely make this often and next time I have coconut flour, will make it that way too.
Thanks for sharing your substitute!
I’m a huge lemon fan. As I write this, I’m sipping on my warm lemon water. It’s a great way to start the day. Your lemon mug cake looks so pretty. I love the light yellow color. Plus it looks incredibly light in texture too. A winner for sure. Pinning!
Why thank you! I am a lemon lover too. I have never made a mug cake and this one looks like a great way to bring in the spring.
I make this amazing chocolate mug cake and soooo needed a new recipe to mix things up. My hubbby thanks you 🙂
I love lemon desserts SO much. I have never made a mug cake…I think this is the perfect one for me to start with. Looks so delicious!
You mean 4X to perfection! This is my kind mug cake! I also love the nutritional info too! Means I can have it!
This might be my favorite mug cake of yours…and I’ve been loving all of them! It screams spring and I’m ready!
Can I use lemon juice instead of lemon extract in this ?
I’m sorry I thought I was still on the lemon pound cake. So my question should be posted on that page please.
Such a nice shade of lemon 🙂
I Love your recipes! my only comment/request is that you include fiber! esp since you are sugar free, it is important to know how much fiber is in there to subtract from the carbs if you carb count. thank you!
Hi Sarah, not sure why you mention it because every single recipe has nutrition info and fiber is included in all of my recipes. I also all ready wrote the net carbs in the notes of the recipe.
I’m allergic to egg. Can I use a flax egg instead?
I don’t see why not although I’ve not tried it. If you do, please come back and let me know how it was.
Do you know if this is gluten free? Thank You
I need spring to come and I need this lemon cake, as well!! Lemon makes me think of warmer weather 🙂
I am a lemon lover, through and through, though have never tried that cure for a sore throat. I’ll have to try that one! This mug cake looks like the perfect dessert for springtime.
I am allergic to coconut.Is there another flour that would work in this recipe?
Any gluten free flour would work.
Could sunflower seed flour work? Allergic to nuts and have to avoid coconut flour while on low fodmap diet. 🙁
Garbanza Bean Flour or Almond Flour would work and remain low carb and higher protein 🙂
I am a huge lemon lover and this looks completely dreamy, Brenda!
I think you’re making this 4x assured perfection, because it looks to me as if you’ve achieved it! I love lemon desserts and lemon any thing. A lovely burst of spring in this lemon mug cake, Brenda!