Air Fryer Peanut Butter Mug Cake (5 Ingredients, No Egg)

Air Fryer Peanut Butter Mug Cake — five pantry ingredients, one mug, and eleven minutes from craving to spoon. There is no egg, no mixer, and no mixing bowl to wash. Just flour, sugar, baking powder, milk, and creamy peanut butter stirred together and set into the air fryer until the top springs back. If you have never baked a mug cake in the air fryer, it turns out noticeably better than the microwave version — the dry circulating heat gives you a real cake crumb instead of a rubbery, over-steamed puck.

Why You’ll Love This Peanut Butter Mug Cake

• Faster than preheating an oven for a dessert that serves one.
• Five ingredients, all pantry staples. Nothing here requires a store run.
• No egg. Which means no half-scrambled bits, and it works if you’re out of eggs or baking egg-free.
• Genuinely single-serving. No leftover half-cake sitting on the counter tempting you at midnight.
• One mug to wash. You can mix the batter directly in the mug if you don’t mind a slightly less even crumb.

Ingredients Needed

The full measurements and printable directions are in the recipe card at the bottom of this post, along with nutrition information.

• All-purpose flour — the structure of the cake. Three tablespoons is all you need. Spoon it into the measuring spoon and level it; packed flour is the number one reason a mug cake comes out dense.
• Granulated sugar — sweetens and keeps the crumb tender. You can swap in light brown sugar for a slightly deeper, caramel note; the texture will be marginally softer.
• Baking powder — the lift. Mug cakes have no egg to help them rise, so this is doing all the work. Check that yours is fresh: drop a pinch into hot water, and if it doesn’t fizz, replace it.
• Milk — moisture. Whole milk gives the richest result, but any dairy or non-dairy milk works.
• Creamy peanut butter — flavor, fat, and moisture in one ingredient. Standard shelf-stable creamy peanut butter behaves most predictably here.

Optional, for the top: whipped cream, peanut butter chips, chocolate chips, chopped roasted peanuts, or a spoonful of warmed peanut butter drizzled over.

How To Make Air Fryer Peanut Butter Mug Cake

Step 1: Mix the dry ingredients with the milk. In a small bowl, stir the flour, sugar, and baking powder together, then add the milk and stir until you have a smooth batter with no dry pockets at the bottom.

Step 2: Fold in the peanut butter. Add the peanut butter and fold it through until the batter is one even color. Stop as soon as it comes together — overmixing develops gluten and gives you a tough, chewy cake.

Step 3: Fill the mug. Lightly grease an oven-safe mug or ramekin and spoon the batter in. Don’t fill past two-thirds — this cake climbs.

Step 4: Air fry at 330°F for 5–6 minutes. Use the air fry setting. Start checking at five minutes.

Step 5: Cool briefly, then top and serve. Give it two minutes to set before you add whipped cream or peanut butter chips, or the topping slides straight off.

How To Tell When It’s Done

Slide a toothpick into the center. A few moist crumbs clinging to it means it’s ready; wet batter means give it another 30–60 seconds. The top should look dry and spring back lightly when you press it.

Air fryers vary more than any other appliance in a home kitchen — basket models run hotter than oven-style ones, and a mug in a crowded basket cooks slower. If you’re still getting a feel for yours, the air fryer charts and tips are worth bookmarking. Err on the side of underbaking. A mug cake with a slightly gooey center is delicious. An overbaked one is dry and there is no saving it.

Tips For The Best Mug Cake

• Grease the mug, even a nonstick-glazed one. Cooking spray or a swipe of butter.
• Use a straight-sided mug rather than a flared one. It bakes more evenly and the cake doesn’t dome and crack.
• Skip natural peanut butter if you can. The kind you have to stir separates in the batter and can leave an oily layer at the bottom. If it’s what you’ve got, stir it thoroughly first and expect a slightly denser cake.
• Level your flour. Worth repeating.
• Eat it warm. Mug cakes firm up considerably as they cool. This one is at its best about three minutes out of the basket.

Variations

Peanut butter takes well to almost anything. Stir a tablespoon of cocoa powder into the dry ingredients and add an extra teaspoon of milk for a chocolate–peanut butter version, or press a few chocolate chips into the top of the batter before it goes in — the same trick that makes the air fryer chocolate chip mug cake work so well. A quarter of a mashed ripe banana folded in turns it into something closer to a peanut butter banana bread. Half a teaspoon of vanilla extract rounds out the flavor if you have it open, and a small pinch of salt makes the peanut butter taste more like peanut butter.

If it’s the format you like more than the flavor, cookie butter behaves almost identically to peanut butter in a batter — the air fryer cookie butter cakes are the obvious next thing to try. Come fall, the air fryer pumpkin mug cake is the one I make most, and there’s a whole collection of air fryer mug cakes if you want to work through them.

Storage

Mug cakes are built to be eaten immediately and they do not keep well — the crumb goes dry and crumbly within a few hours. If you want to get ahead, mix the batter, cover the mug, and refrigerate it for up to 24 hours; stir it once and add a minute to the cook time. Leftover baked cake can be covered and refrigerated overnight, then warmed for 15–20 seconds in the microwave with a damp paper towel over the top.

Air Fryer Peanut Butter Mug Cake FAQs

Can I make this peanut butter mug cake in the microwave?

Yes. Microwave on high for 60–90 seconds, checking at 60. The texture is spongier and slightly more rubbery than the air fryer version, but it works when speed matters most.

Is this mug cake egg-free?

It is. There’s no egg in the recipe at all — the baking powder handles the rise. For a fully vegan version, use a non-dairy milk and check that your peanut butter contains no honey.

Can I use crunchy peanut butter?

Yes. The cake will have peanut pieces running through it and a slightly less uniform crumb, which some people prefer. No other adjustments needed.

Can I make this gluten-free?

Use a measure-for-measure gluten-free all-purpose blend in place of the flour. Blends containing xanthan gum work best; the cake will be a touch denser.

Can I use almond, oat, or coconut milk?

Any milk works. Oat milk gives the closest result to dairy. Coconut milk adds a mild coconut flavor that pairs well with peanut butter.

Can I reduce the sugar?

You can drop to one tablespoon for a less sweet cake. Sugar substitutes like erythritol or monk fruit blends will work, though the cake browns less and the crumb comes out slightly drier.

Can I cook two mug cakes at once?

Yes, as long as there’s air space around each mug. Crowding the basket blocks circulation and you’ll get uneven, undercooked centers. Add a minute and check both.

What size mug should I use?

A standard 10–12 oz oven-safe ceramic mug or ramekin. Make sure it fits your basket with clearance above it — the cake rises. Anything labeled oven-safe is safe in an air fryer.

Serving Suggestion

A scoop of vanilla ice cream melting into a warm peanut butter mug cake is hard to beat. Otherwise: whipped cream, a drizzle of warmed peanut butter, or a handful of peanut butter chips scattered over the top while it’s still hot enough to soften them.

Made this? I’d love to see it. Tag @forktospoon on Instagram or share a photo in the Air Fryer Recipes Facebook group — and if you enjoyed it, leaving a star rating on the recipe card below helps other readers more than you’d think.