100 calorie mug cake
This 100-calorie mug cake proves a chocolate fix does not have to wreck your day: a fluffy, cocoa-rich little cake leavened with a fizz of baking soda and vinegar instead of eggs and butter. A zero-calorie sweetener and just half a teaspoon of oil keep it light, while the cocoa still lands a real chocolate hit, all in about a minute in the microwave.
Why you'll love this
- A single serving lands right around 100 calories, with built-in portion control and no tempting leftovers
- Egg-free and nearly fat-free, leavened by a baking soda and vinegar reaction for a genuinely light, fluffy crumb
- Real chocolate flavour from cocoa powder, not a watery diet compromise
- Ready in about a minute in the microwave, or baked in the oven if you prefer
Key ingredients & swaps
- All-purpose flour — just a tablespoon forms the structure while keeping the calorie count low; spoon and level it so the cake does not turn dense.
- Cocoa powder — carries the chocolate flavour for almost no calories; natural (not Dutch-process) cocoa is slightly acidic and reacts with the baking soda for a better rise.
- Baking soda and white vinegar — the egg-free engine of the cake; the vinegar reacts instantly with the baking soda to create the bubbles that lift it, and you will not taste the vinegar at all.
- Zero-calorie sweetener — sweetens without the sugar calories; use a granulated 1:1 sugar replacement so the volume and texture stay right.
- Oil — just half a teaspoon coats the flour and keeps the crumb moist rather than dry and chalky, without adding much fat.
How to make it (step by step)
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1
Prep the mug
Use a microwave-safe mug of at least 8 oz (240 mL) so the batter has room to puff up. A quick spritz of cooking spray helps the cake release cleanly if you want to turn it out.
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2
Whisk the dry mix
Combine the flour, sweetener, cocoa powder, a pinch of salt and the baking soda, breaking up any cocoa lumps. Even mixing here prevents bitter pockets of raw cocoa or soda.
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3
Add the wet and watch it fizz
Stir in the vinegar, oil, vanilla and water (or milk) until smooth; you will see it bubble as the soda and vinegar react, which is exactly what lifts an egg-free cake. Fold in the chocolate chips now if using, and stop stirring once combined.
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4
Cook until just set
Microwave on high for about 60 seconds, until the top looks set and springs back; add 10-second bursts only if the centre is still wet. To bake instead, pour into a ramekin and bake at 350F (175C) for 10 to 12 minutes.
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5
Cool briefly and enjoy
Let it rest 1 to 2 minutes so it firms up and cools from scalding. Because there is no egg, a slightly soft, fudgy centre is fine and actually nicer than an overcooked one.
Pro tips
- Pull it the instant the top is set; overcooking is what turns a light mug cake rubbery and dry, and an egg-free batter is forgiving if the middle stays a touch soft.
- Use natural unsweetened cocoa rather than Dutch-process, because the soda needs cocoa's acidity to react and give you the rise and deeper chocolate flavour.
- Make sure your baking soda is fresh; a stale tin gives a flat, dense cake no matter how well you mix.
- Add the chocolate chips only if you have calorie room, since they will push the total above 100.
Variations
- Mocha: stir in a pinch of instant espresso or coffee to deepen the chocolate without adding calories.
- Peppermint: add a drop of peppermint extract for a thin-mint vibe.
- Lighter still: skip the chocolate chips and use water rather than milk to keep it at its leanest.
Storage & freezing
This one is built to be made and eaten on the spot; it has no leftovers by design, and an egg-free, low-fat mug cake dries out fast, so it does not keep or reheat well.
Recipe
100 calorie mug cake
Ingredients
- 1 tbsp all-purpose flour
- 1 tbsp granulated sweetener (zero-calorie preferred)
- 1 tsp cocoa powder
- Pinch of salt
- ⅛ tsp baking soda
- ¼ tsp white vinegar
- ½ tsp oil
- Dash of vanilla extract
- 1 tbsp water (or milk)
- 1 tsp chocolate chips (optional)
Instructions
- Prepare Mug: Use a microwave-safe mug (8 oz/240 mL).
- Mix Dry Ingredients: Combine flour, sweetener, cocoa powder, salt, and baking soda.
- Add Wet Ingredients: Stir in vinegar, oil, vanilla, and water (or milk) until smooth. Fold in chocolate chips if using.
- Cook:
- Microwave: Cook on high for 60 sec (add 10-sec intervals if needed).
- Oven: Bake at 175°C (350°F) for 10–12 mins.
- Cool & Serve: Let cool for 1–2 minutes, then enjoy.
Nutrition · per serving (estimate)
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Frequently asked questions
Is this mug cake really only 100 calories?
Roughly, yes, when made as written with a zero-calorie sweetener and no chocolate chips. The bulk of the calories come from the tablespoon of flour and the half teaspoon of oil; adding chips, sugar or extra oil will push it higher.
Why does it use vinegar and baking soda instead of egg?
The vinegar reacts with the baking soda to produce bubbles that make the cake rise, doing the lifting job an egg would. It keeps the cake egg-free and lower in calories, and the small amount of vinegar leaves no taste behind.
Can I taste the vinegar in the finished cake?
No. The tiny amount fully reacts with the baking soda during mixing and cooking, so it only acts as a leavener and disappears into the chocolate flavour.
What sweetener works best?
A granulated zero-calorie sweetener that measures 1:1 like sugar, such as an erythritol or monk-fruit blend, keeps both the calories and the texture right. Liquid sweeteners can throw off the batter's moisture.
Why did my low-calorie mug cake turn out rubbery?
Usually overcooking or overmixing. Microwave only until the top is just set, stir just until smooth, and remember an egg-free cake is fine left slightly soft in the middle.
Can I bake it in the oven instead of microwaving?
Yes. Pour the batter into an oven-safe ramekin and bake at 350F (175C) for about 10 to 12 minutes, until set. The texture comes out a little more evenly cakey than the microwave version.
Does the type of cocoa powder matter?
It does here. Use natural unsweetened cocoa rather than Dutch-process, because the baking soda relies on natural cocoa's acidity to react and give the cake its rise and richer flavour.
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