This is a single blueberry muffin made in a mug in the microwave. The batter is an egg, melted butter, almond flour, coconut flour, baking powder, erythritol and blueberries, and it cooks in 90 seconds. The card gives 4 grams of carbohydrates for the one muffin, and the recipe makes 1 serving.
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Prep takes 2 minutes and cooking takes 1 minute 30 seconds, so the whole thing is done in 3 minutes 30 seconds. There is one mug to wash, and you can eat the muffin straight from it.
What Goes into the Mug
The card at the bottom has the full list. It uses very small amounts.
- Egg (1 large) and unsalted butter (1 tablespoon, melted): whisked together first.
- Almond flour (1 tablespoon) and coconut flour (1 tablespoon): the dry base.
- Baking powder (1 teaspoon) and a pinch of salt: lift the muffin and balance the sweetness.
- Erythritol (1 tablespoon): the sweetener. The card says you can use your preferred keto sweetener.
- Fresh blueberries (2 tablespoons): folded in gently at the end.
Mixing and Microwaving
Whisk the egg and melted butter together in a microwave-safe mug until well combined. Add the almond flour, coconut flour, baking powder, erythritol and salt and mix until smooth. Fold in the blueberries gently.
Microwave on high for 90 seconds. Check whether it is done, and if it is not, add more time in 10-second steps until it is fully cooked. Let it cool for a minute so it sets, then eat it from the mug or turn it out onto a plate.
Tips for Mug Muffins
- Use a large mug: the muffin rises, and a 12-ounce mug gives it room so it does not overflow.
- Know your microwave: wattage varies. If the center is not cooked after 90 seconds, add 10 seconds at a time and watch it so it does not overcook.
- Pick a sweetener: monk fruit or stevia can replace erythritol. Adjust the amount to taste.
- Add flavor: a dash of vanilla extract or a sprinkle of cinnamon goes into the batter.
- Top it: sugar-free yogurt or chopped nuts add texture.
Ways to Change It

- Other berries: raspberries or blackberries in place of the blueberries, or a mix of blackberries and strawberries.
- Chocolate chip: add a tablespoon of sugar-free chocolate chips to the batter.
- Cinnamon: mix in a teaspoon of cinnamon, or sprinkle cinnamon and erythritol on top before microwaving for a swirl effect.
- Banana: fold in half a small ripe banana, mashed. Bananas are higher in sugar than the other fruit here, so the carbs go up.
- Peanut butter: stir in a tablespoon of natural peanut butter.
- Almond: a few drops of almond extract, with sliced almonds on top for crunch.
What to Serve With It
Black coffee, unsweetened almond milk or herbal tea work as drinks. For a bigger breakfast, add scrambled eggs, avocado slices, or full-fat unsweetened Greek yogurt with cinnamon or a few berries. Chia seed pudding made with almond milk is another low-carb side, and a spoonful of almond or peanut butter on the side adds protein.
Nutrition per Muffin
One muffin has approximately 210 calories, 18 grams of fat (7 grams saturated), 4 grams of carbohydrates, 2 grams of fiber, 1 gram of sugar, 6 grams of protein and 200 milligrams of sodium.
FAQ
Can you use frozen blueberries?
Yes. Add them directly from the freezer to avoid extra moisture in the batter.
What can replace almond flour?
Sunflower seed flour works as a nut-free option, though it may change the flavor slightly.
How do you store leftovers?
In an airtight container in the refrigerator for up to 2 days. Reheat in the microwave.
Can you make it in advance?
It is best fresh, but you can mix the dry ingredients ahead in a jar. When you are ready, add the wet ingredients and microwave.
Is it good for meal prep?
You can prepare the batter in several mugs and microwave them one at a time as needed.
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Written and edited by The Foodie Yummy Kitchen Team
The Foodie Yummy Kitchen Team writes and edits the recipes on Foodie Yummy: classic American potluck salads, holiday sides and easy comfort food, with a few low-carb options. Every recipe lists exact quantities, numbered steps and a printable recipe card, plus notes on swaps, storage and make-ahead timing. Spot a problem with a recipe? Tell us through the contact page and we will correct it. About us
Keto 90-Second Blueberry Muffin: Quick and Delicious Recipe!
Ingredients
Instructions
In a microwave-safe mug, whisk together the egg and melted butter until well combined.
Add the almond flour, coconut flour, baking powder, erythritol, and salt to the mug. Mix until smooth.
Gently fold in the blueberries.
Microwave on high for 90 seconds. Check for doneness; if needed, microwave in additional 10-second intervals until fully cooked.
Let the muffin cool for a minute before enjoying directly from the mug or transferring to a plate.
Notes
For added flavor, sprinkle some cinnamon or vanilla extract into the batter.
You can substitute blueberries with other low-carb berries like raspberries or blackberries for variation.
Nutrition
| Serving Size | 1 muffin |
|---|---|
| Calories | 210 calories |
| Sugar Content | 1g |
| Sodium Content | 200mg |
| Fat Content | 18g |
| Saturated Fat Content | 7g |
| Unsaturated Fat Content | 11g |
| Trans Fat Content | 0g |
| Carbohydrate Content | 4g |
| Fiber Content | 2g |
| Protein Content | 6g |
| Cholesterol Content | 186mg |
