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

Keto Peanut Butter Mug Cake

Keto Chocolate Mug Cake

Keto Cannoli Mug Cake

Keto Red Velvet Mug Cake

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