It was one of those nights. You know the kind—too late to start baking, too tired to leave the house, but that sweet tooth is demanding attention right now. I opened my pantry and found a jar of peanut butter, some sugar, and eggs.
Three ingredients. That’s when I remembered this ridiculously simple mug cake that’s saved me countless times.
This 3-ingredient peanut butter mug cake is the dessert equivalent of a magic trick. You literally just mix, microwave, and eat.
No flour, no measuring cups full of ingredients, no waiting around. Just pure peanut butter goodness that’s warm, sweet, and ready in about a minute.
The texture lands somewhere between a soft cookie and a fluffy cake, and honestly? It tastes like you put in way more effort than you actually did.
Why You’ll Love This Easy Mug Cake Recipe
- Ready in 60 seconds
- Only 3 ingredients
- No flour
- Perfect single serving
3-Ingredient Peanut Butter Mug Cake
| Ingredient | Amount |
| Large egg | 1 |
| Creamy peanut butter | 3 tablespoons |
| White sugar | 2 tablespoons |
| Mini chocolate chips (optional) | 1 1/2 teaspoons |
Instructions
Step 1: Whisk Everything Together
Grab a small mixing bowl and crack in your egg. Add the peanut butter and sugar, then whisk it all together until you’ve got a smooth, uniform batter with no streaks. This should take about 30-45 seconds of good whisking. The mixture will be thick and a beautiful golden color when it’s ready.
Step 2: Pour Into Your Mug
Transfer the batter into a microwave-safe mug or ramekin—make sure it’s at least 10-12 ounces so you have room for the cake to rise. If you’re using those mini chocolate chips, sprinkle them right on top of the batter now. They’ll melt into little pockets of chocolate heaven.
Step 3: Microwave and Wait
Pop your mug in the microwave and cook on high for 45 seconds to 1 minute. Start with 45 seconds and check—if it still looks wet on top, give it another 10-15 seconds. Every microwave is different, so you might need to adjust. Once it’s done, let it sit for a full minute before digging in. I know waiting is hard, but this step lets it set properly and cool down from molten lava temperature.
Ingredient Swaps & Substitutions
Egg-free option: Mix 1 tablespoon ground flaxseed with 2.5 tablespoons water and let it sit for 5 minutes before using. The texture will be denser but still tasty.
Nut allergy? Try sunflower seed butter or wow butter (soy-based) in place of peanut butter. The flavor changes but it still works.
Sugar alternatives: Coconut sugar, honey (use 1.5 tablespoons), or maple syrup all work. Each brings its own flavor twist.
Almond butter version: Swap peanut butter for almond butter for a milder, slightly sweeter taste.
Storage & Make-Ahead
- Best eaten fresh
This mug cake is meant to be devoured right after making it. The texture is fluffiest when it’s fresh and warm.
- Refrigerating leftovers
If you somehow have leftovers, cover the mug with plastic wrap and refrigerate for up to 24 hours. Reheat in the microwave for 15-20 seconds before eating. Fair warning—it won’t be quite as fluffy as when it was fresh.
- Freezing
Not recommended. Mug cakes get rubbery and weird when frozen and thawed. Since this takes literally one minute to make, just whip up a fresh one when the craving hits.
Nutritional Information
Per Serving (Makes 1 mug cake)
| Nutrient | Amount |
| Calories | 380 |
| Total Fat | 22g |
| Saturated Fat | 5g |
| Cholesterol | 185mg |
| Sodium | 175mg |
| Total Carbohydrates | 33g |
| Dietary Fiber | 2g |
| Sugars | 27g |
| Protein | 14g |
Serving Suggestions
- Eat warm straight from the mug with a spoon
- Top with a scoop of vanilla ice cream for contrast
- Drizzle with melted chocolate or caramel sauce
- Add sliced bananas on top for extra sweetness
- Dollop with whipped cream and extra chocolate chips
- Serve alongside fresh berries to balance the richness
- Dust with powdered sugar for a fancy finish
FAQs
Why is my mug cake rubbery?
You probably overcooked it. Mug cakes keep cooking after you remove them from the microwave, so it’s better to slightly undercook than overcook. Try reducing your time by 10 seconds next time.
Can I use natural peanut butter
I wouldn’t recommend it. Natural peanut butter has separated oils that can make the cake greasy and affect the texture. Regular creamy peanut butter works best here.
It overflowed in my microwave!
Your mug was too small. Use at least a 10-12 ounce mug and fill it only about halfway. The batter rises significantly as it cooks.
Is this gluten-free?
Yes! There’s no flour in this recipe, so it’s naturally gluten-free. Just make sure your peanut butter doesn’t have any hidden gluten-containing additives.
The Bottom Line
Here’s the thing about this 3-ingredient peanut butter mug cake—it’s not trying to be fancy. It’s not pretending to be some elaborate dessert that took hours to perfect. It’s just honest, straightforward comfort in a mug that happens to be ready faster than you can scroll through your phone.
The best part is that you probably have everything you need in your kitchen right now. No special ingredients, no fancy equipment, no complicated techniques. Just three simple things that transform into something warm and delicious in about 60 seconds.
