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Jumbo Chocolate Chunk Muffins Recipe (Costco Copycat)

Jumbo Chocolate Chunk Muffins inspired by Costco Chocolate Muffins.  These muffins are easily made using a cake mix and chocolate chunks.  These muffins are great for breakfast or dessert!

Jumbo Chocolate Chunk Muffins

Costco copycat jumbo chocolate chunk muffin cut in half to show melted chocolate inside.
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I don't know if you have ever had a Costco Chocolate Muffin before but they are so delicious and they're huge! The "secret" ingredient for their muffins is really just cake mix!

So much for thinking they were nutritious, huh? I always thought they were too delicious to really be breakfast food. My kids enjoy these muffins and I will be making more varieties soon! I'm thinking blueberry and cinnamon streusel!

When I made these muffins I filled them almost full. If you want muffins with huge muffin tops I would suggest only make about 6 muffins and fill the liners a little more to achieve the muffin top you desire.

These muffins came out really well and I think next time I make them I may double my batch and have larger and more muffins! It's not even 24 hours later and these muffins are gone! They're that good!

When these Jumbo Chocolate Chunk Muffins came out of the oven my house filled with the smell of chocolate. It was so wonderful and my son couldn't wait to try one.

The chocolate chunks melting into the muffin only made the wait even harder for him!

Costco copycat jumbo chocolate chunk muffins without wrapper beside a glass of milk.

Costco Copycat Jumbo Chocolate Chunk Muffins Recipe

Overall, I was very pleased with the way these muffins turned out and everyone in the house really enjoyed them. Every bite had a chocolate chunk it had the great texture of a muffin. I call them a success! I'd say my family thinks so, too!

RELATED: Chocolate Chip Cookies (DoubleTree Copycat) 

A hand holding out a large chocolate muffin with fresh raspberries and chocolate pieces on a white plate.

Looking for cupcake recipes? Check these out!

📖 Recipe

Yield: 8 muffins

Jumbo Chocolate Chunk Muffins Recipe

Jumbo Chocolate Chunk Muffins Recipe

These muffins are inspired by Costco bakery muffins.  With a chocolate chunk in every bite, these muffins are full of flavor and full of chocolate. 

Prep Time 5 minutes
Cook Time 10 minutes
Total Time 15 minutes


  • 1 15 oz. box chocolate cake mix
  • 1 cup milk
  • ¾ stick butter, melted
  • 2 teaspoon baking powder
  • 1 bag chocolate baking chunks
  • 3 eggs


  1. Preheat oven to 375°
  2. Line jumbo muffin tins with liners.
  3. Combine melted butter, eggs, milk, and baking powder in large mixing bowl.
  4. Add in chocolate cake mix, stir until blended.
  5. Stir in chocolate chunks, just until mixed.
  6. Fill liners ¾ way full or fuller for less muffins but higher muffin top (will get less muffins this way).
  7. Bake for about 20 minutes. Check muffin with toothpick. They are done with muffins come out clean - do not over bake. They will become dry.
  8. Remove from muffin tins to remove from heat.


Tip:  To achieve a fuller muffin fill liners all the way. 

Tip:  Resist the temptation to open the oven while the muffins are rising.  It will cause the muffins to fall. 

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Nutrition Information:



Serving Size:

1 grams

Amount Per Serving: Unsaturated Fat: 0g

Did you make this recipe?

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Starla Kalkbrenner

Tuesday 31st of October 2023

I just made these and they are absolutely amazing. I added some coffee to mine and some marshmallows as well. They turned out to be amazing 🤩 I think ALOT of the things I bake has to do with the way you think about what you are doing. If you go into the kitchen questioning everything and saying to yourself this recipe is not going to work out I guarantee you are going to have issues. But if you walk in the kitchen and are confident in what you are making you will be amazed. I love baking and I try all sorts of recipes. 3/4 of them come out wonderful 👍


Wednesday 1st of November 2023

Love the addition of marshmallows and coffee! :)

Mom on the go

Thursday 9th of June 2022

These were not good....texture was off, likely to calling for too many eggs? It is chewy and gross...

The cooking time was wayyy off... maybe I did something wrong but I reread the recipe multiple times prior to baking!

Do not reccomend.


Sunday 29th of May 2022

Curious if these would work with a cream cheese filling added before baking?many thanks


Tuesday 31st of May 2022

Hi Allison, I have not tried that but it sounds yummy! Let me know if you try it.

Melinda Fernie

Monday 18th of April 2022

I'm making these right now and just the batter supposed to be so thick? Almost like a mouse texture.


Monday 18th of April 2022

Yes, the batter will be thick. :)


Saturday 7th of December 2019

Made these twice and they turned out perfect each time. ❤️

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