Easy Peanut Butter Cup Mug Cake

Okay, friends, I have to confess: sometimes I just want cake, and I want it NOW. Enter this Easy Peanut Butter Cup Mug Cake — a little miracle that cooks up in under 5 minutes right in your microwave. I’m talking warm, fluffy cake with gooey pockets of peanut butter cup magic melting into every bite. The smell alone makes you want to dive right in, and since it’s made in a mug, there’s almost no clean-up. Honestly, it feels like cheating, but this cozy, sweet treat is real life. Whether you’re craving a quick dessert fix after a long day or need a last-minute sweet for movie night, this recipe has your back (and your sweet tooth). Grab your favorite mug, and let’s get this peanut-buttery party started!

Quick Facts

• Yield: 1 mug cake
• Prep Time: 3 minutes
• Cook Time: 1 minute 30 seconds
• Total Time: 5 minutes

Ingredients

For the Main Dish:

• 4 tbsp all-purpose flour
• 2 tbsp granulated sugar
• 1/8 tsp baking powder
• Pinch of salt
• 3 tbsp milk (any kind)
• 1 tbsp vegetable oil
• 1 tbsp peanut butter (creamy works best)
• 2 mini peanut butter cups, chopped

How I Make It

Step 1:

In a microwave-safe mug, whisk together flour, sugar, baking powder, and salt until combined and lump-free. This dry foundation ensures the cake rises just right.

Step 2:

Add the milk, vegetable oil, and peanut butter. Stir it all together until the batter is smooth and creamy, with that soft peanut butter swirled through.

Step 3:

Fold in the chopped mini peanut butter cups gently. Some will sink a little, creating pockets of melty sweetness once cooked.

Step 4:

Pop the mug in the microwave and cook on high for about 90 seconds. Watch carefully—cooking times may vary with microwave wattage, so start with 75 seconds and add more if needed. The cake should be set but still moist.

Step 5:

Let your mug cake rest for a minute; it’s piping hot with molten chocolate and peanut butter flowing through every bite.

Step 6:

Grab a spoon and dive in! Optionally, top with a drizzle of chocolate syrup or a sprinkle of chopped peanuts for extra crunch and glam.

Variations & Tips

• Swap peanut butter cups for Reese’s Pieces or chopped chocolate chips for a different texture.
• Use natural peanut butter, but add a little extra sugar if you like it sweeter.
• Add a pinch of cinnamon or a drop of vanilla extract for a flavor twist.
• Microwave power varies—start with less time and check often to avoid overcooking.
• If batter is too thick, add a splash more milk for a lighter crumb.
• For a fudgier cake, reduce flour by 1 tbsp and add 1 tbsp cocoa powder (optional!).

How I Like to Serve It

This mug cake is perfect solo, but I love to serve it with a scoop of vanilla ice cream or a dollop of whipped cream for weekend indulgences. It also makes a quick fix for after-school snacks during chilly fall evenings when you want something warm and chocolatey without fuss. For Valentine’s Day or a cozy movie night, grab your favorite mug and enjoy this nostalgic little treat!

Notes

• Best eaten immediately, but you can cover and refrigerate leftover batter for up to 1 day (though it’s rarely leftover!).
• Reheat in the microwave for 15–20 seconds if the cake cools down before you finish.

Closing: This Easy Peanut Butter Cup Mug Cake is my go-to when I want instant comfort, proof that sometimes the simplest treats bring the biggest smiles.