3 Incredibly Easy 3-Ingredient Flourless PB Mug Cake (Ready in 2 Minutes!)

3-Ingredient Flourless PB Mug Cake is the kind of recipe you make when the chocolate craving hits… and you refuse to turn on the oven. Just peanut butter, egg, and sugar — stirred in a mug and microwaved into warm, soft, cake-like magic.

The first time I made this, it was late. The house was quiet. I wanted something sweet but didn’t want dishes, mess, or leftovers tempting me all week. Two minutes later? I was sitting on the couch with the fluffiest little peanut butter cake and wondering why I hadn’t made it sooner.

Thank you for being here. Truly. These tiny, simple recipes are some of my favorites to share. If you love quick comfort treats like this, make sure you subscribe to my email list so you never miss a cozy kitchen moment.

Let’s make dessert in a mug.

Overview of Recipe Content

This 3-Ingredient Flourless PB Mug Cake is:

• Gluten-free
• Flourless
• High-protein
• Made in under 3 minutes
• Perfect single-serving dessert

It’s ideal for:

• Late-night cravings
• After-dinner treat
• Quick protein snack
• When you want dessert without baking a full batch

Why You’ll Love It

• Only 3 pantry ingredients
• No flour required
• No mixer needed
• No leftovers
• Warm, soft texture

What It Tastes Like

It’s soft, tender, and slightly dense — almost like a cross between a peanut butter cake and a molten center cookie. The peanut butter flavor shines, and the sugar gives just enough sweetness without overpowering it.

Add chocolate chips? Oh yes. Game changer.

Nutritional Highlights

• Peanut butter adds protein and healthy fats
• Egg provides structure and richness
• Naturally gluten-free

If you love easy peanut butter desserts, try my 3-Ingredient Banana PB Brownies or Peanut Butter Banana Greek Yogurt Cookies next. Save them to your Pinterest board at https://www.pinterest.com/poulefrecipe/ for later.

Ingredients

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• 3 tablespoons peanut butter
• 1 large egg
• 1 tablespoon sugar

That’s it. Three ingredients. One mug.

Tools You’ll Need

• Microwave-safe mug
• Fork or small whisk
• Microwave

Substitutions & Additions

Want to customize?

• Use brown sugar for deeper flavor
• Add 1 tablespoon chocolate chips
• Sprinkle flaky sea salt on top
• Add a dash of vanilla extract
• Stir in 1 tablespoon cocoa powder for chocolate version

How to Make 3-Ingredient Flourless PB Mug Cake

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Step 1: Mix in the Mug

Add peanut butter, egg, and sugar directly into a microwave-safe mug.

Whisk with a fork until completely smooth. Make sure egg is fully incorporated — no streaks.

The batter should look creamy and slightly thick.

Step 2: Microwave

Microwave on high for 45–60 seconds.

Cooking time may vary depending on your microwave. Start with 45 seconds. The top should look set but still slightly soft in the center.

Step 3: Rest

Let it sit for 1 minute. It will continue cooking slightly from residual heat.

Step 4: Enjoy

Eat straight from the mug while warm.

Add toppings if desired:

• A spoonful of yogurt
• Melted chocolate drizzle
• Powdered sugar
• Fresh berries

What to Serve with It

• Glass of milk
• Coffee or espresso
• Vanilla ice cream
• Greek yogurt

Honestly? It’s perfect all on its own.

Tips for Making It Perfect

• Do not overcook — it can turn rubbery.
• Mix thoroughly to avoid egg pockets.
• Use creamy peanut butter for best texture.
• If too dense, microwave 5–10 seconds less next time.
• Let it cool slightly before diving in.

Storage Instructions

This recipe is best eaten immediately.

Because it contains egg and is microwave-cooked, it’s not ideal for storing. If you must save it, refrigerate and reheat gently — but fresh is best.

General Information

Mug cakes are one of my favorite kitchen shortcuts. They give you all the comfort of baking without the time or cleanup. This flourless peanut butter version is naturally gluten-free and incredibly satisfying.

It’s the kind of recipe you memorize after making it once.

Three ingredients. Two minutes. Zero regrets.

Frequently Asked Questions

Can I make it without sugar?

You can use maple syrup or a sugar substitute, though texture may vary.

Can I make it dairy-free?

It’s already dairy-free if using standard peanut butter.

Why is my mug cake rubbery?

It was likely overcooked. Reduce microwave time slightly.

Can I double it?

Yes, but use a larger mug and increase cooking time slightly.

Is it high in protein?

Yes, thanks to peanut butter and egg — approximately 12–14g protein per serving.

Conclusion

This 3-Ingredient Flourless PB Mug Cake is warm, soft, rich, and unbelievably easy. It’s perfect when you want dessert right now without baking a full tray.

If you loved this quick treat, try my 3-Ingredient Banana PB Brownies or Peanut Butter Banana Greek Yogurt Cookies next for more peanut butter magic.

Thank you for baking with me — even if it’s just in a mug tonight.

Interactive Elements

If you try this mug cake, leave a comment and star rating below.

Share your cozy mug dessert on Pinterest and tag me at https://www.pinterest.com/poulefrecipe/ so I can see your creations.

Nutritional Information (Approximate per mug cake)

Nutrient	Amount
Calories	340
Protein	14g
Carbohydrates	14g
Sugar	12g
Fat	26g
Saturated Fat	5g
Fiber	2g
Sodium	140mg

Values vary depending on peanut butter used.

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