Keto Mug Cake (90 Seconds)

A keto mug cake made with almond flour and cocoa powder comes out to about 4 g net carbs per serving, and it takes about 5 minutes total to make: roughly 3 minutes to mix and 70 to 90 seconds in the microwave. It's a flourless, sugar-free chocolate cake for one, dense and fudgy when you don't overcook it.

A mug cake solves a real problem on keto: most low-carb dessert recipes make a full pan or a dozen cookies, which is a lot of willpower to manage around a single craving. This version uses almond flour instead of wheat flour and a granulated erythritol or allulose sweetener instead of sugar, mixed and cooked in the same mug you eat it from. Below: the exact ingredients, the microwave method, an oven option, flavor swaps, and the full nutrition breakdown.

What ingredients do you need for a keto mug cake?

• 3 tbsp (21 g) blanched almond flour — finely ground almond flour, not almond meal, gives the smoothest texture in a small batch like this.¹
• 1 tbsp (5 g) unsweetened cocoa powder — for the chocolate version; skip it for vanilla.
• 2 tbsp (24 g) granulated erythritol or allulose sweetener — sugar alcohols and allulose are largely not digested, so they don't count toward net carbs the way table sugar does.²
• 1/4 tsp baking powder and a pinch of fine sea salt
• 1 large egg — the structure of the cake; there's no flour gluten here to hold it together otherwise.
• 1 1/2 tbsp (21 g) unsalted butter, melted (or a neutral oil, if you prefer)
• 1 tbsp unsweetened almond milk — thins the batter slightly so it cooks evenly.
• 1/4 tsp vanilla extract
• 1 tbsp sugar-free chocolate chips (optional, for the chocolate version)

For a refresher on which sweeteners, flours, and dairy fit a keto pantry, see the full keto food list.

How do you make a keto mug cake in the microwave?

1. Mix the dry ingredients. Whisk the almond flour, cocoa powder, sweetener, baking powder, and salt directly in a microwave-safe mug.
2. Whisk in the wet ingredients. Add the egg, melted butter, almond milk, and vanilla; whisk until smooth with no dry streaks.
3. Add chocolate chips. Stir in the chocolate chips, if using, pressing a few on top.
4. Microwave in short bursts. Cook on high for 70 to 90 seconds total, checking at 45 seconds, until the center is just set and no longer wet-looking.
5. Rest before eating. Let it sit for 1 minute — it keeps setting from residual heat as it cools slightly.

Can you bake a keto mug cake in the oven instead?

Yes — pour the same batter into a small oven-safe ramekin and bake at 350°F (175°C) for about 12 to 15 minutes, until a toothpick comes out mostly clean. The oven version bakes more evenly, with a firmer, more traditional crumb, but it trades away the 90-second speed that makes the microwave method the point.

How do you keep a keto mug cake from turning rubbery?

Overcooking is the single most common mistake — almond-flour and egg batters go from underdone to rubbery in as little as 15 to 20 extra seconds in the microwave, so short bursts and pulling it slightly early matter more than any ingredient swap. Whisk just until smooth (extra air from overbeating can make the crumb spongy), use a short, wide mug for even cooking, and stop microwaving while the top still looks just barely set — carryover heat finishes the center during the rest.

What flavor variations can you make?

• Vanilla: skip the cocoa powder, add 1 more tablespoon of almond flour in its place, and increase the vanilla extract to 1/2 tsp.
• Peanut butter: stir in 1 tablespoon of natural peanut butter with the wet ingredients, and swap the chocolate chips for a few chopped unsalted peanuts.
• Chocolate (default): as written above — for a molten center, slightly underfill the mug and pull it a few seconds earlier.

Whichever version you make, keep the almond flour, sweetener, egg, and fat ratio the same — that ratio is what sets the texture, not the flavoring.

How many net carbs are in a keto mug cake?

One mug cake has roughly 360 calories, 33 g fat, 32 g total carbs, 4 g fiber, 12 g protein, and 4 g net carbs, after subtracting fiber and the erythritol sugar alcohol from total carbs — the same method used across every recipe on this site.³

Nutrient	Per mug cake
Calories	360 kcal
Total carbs	32 g
Fiber	4 g
Net carbs	4 g
Fat	33 g
Protein	12 g

Run your own numbers, including how this fits your daily target, with the net-carb calculator or the full guide to calculating your keto macros.

Where else can you find keto desserts and recipes?

This recipe lives in our keto recipes by type hub alongside the rest of the sweets, breads, and snacks collection. If you'd rather bake a full batch to share, try the keto chocolate chip cookies, or browse the complete keto dessert recipes roundup for more low-carb sweets. Looking to fit a dessert like this into a full day of eating? See the 7-day keto meal plan for how the numbers work across breakfast, lunch, and dinner.

Frequently Asked Questions

How many net carbs are in a keto mug cake?

About 4 g net carbs per mug cake, based on a single-serving recipe made with almond flour, cocoa powder, and a granulated erythritol or allulose sweetener.

Can you make a keto mug cake without eggs?

Not with this ratio — the egg is what holds a flourless, gluten-free batter together in such a small volume. An egg-free version needs a different structure, like a flax egg, and will have a noticeably softer set.

Why did my keto mug cake turn out rubbery?

Almost always overcooking. Egg-based, flourless batters go from underdone to rubbery within 15 to 20 seconds in the microwave, so cook in short bursts and pull it while the center still looks just barely set.

Can you bake a keto mug cake in the oven instead of microwaving it?

Yes. Pour the same batter into a small ramekin and bake at 350°F (175°C) for about 12 to 15 minutes. It trades the 90-second speed for a firmer, more even crumb.

What sweetener works best in a keto mug cake?

A granulated erythritol or allulose blend measures cup-for-cup like sugar and dissolves well in a small batter. Liquid stevia works too, but you'll need to adjust the almond milk down slightly to keep the batter from being too thin.

Can you double a keto mug cake recipe?

Yes, but split it into two mugs rather than one larger one — a single mug holding double the batter cooks unevenly in the microwave, with rubbery edges before the center sets.

Works cited

1. FoodData Central — Nuts and Flour Nutrient Search, U.S. Department of Agriculture — August 18, 2026 https://fdc.nal.usda.gov/food-search?query=almond%20flour
2. Ketogenic Diet — StatPearls, NCBI Bookshelf — August 18, 2026 https://www.ncbi.nlm.nih.gov/books/NBK499830/
3. Diet Review: Ketogenic Diet for Weight Loss — Harvard T.H. Chan School of Public Health, Nutrition Source — August 18, 2026 https://nutritionsource.hsph.harvard.edu/healthy-weight/diet-reviews/ketogenic-diet/

Article history

1. August 23, 2026Updated
2. August 18, 2026First published