Copycat Costco Chocolate Muffins

If you ever wished you could bring home those giant, decadent Costco chocolate muffins but with a fresher homemade touch, this is the recipe you need. These muffins come out rich and bursting with chocolate in every bite, just as moist and crave-worthy as the store version. They are the best excuse to turn breakfast into a treat, or to make any afternoon coffee break feel special.

I first made these when I could not justify buying a whole dozen from the store. My family devoured the batch in less than a day and now they beg for them on snow days and birthdays.

Ingredients

• All-purpose flour: This gives the muffins structure and keeps them tender. Use fresh flour and spoon it into your measuring cup for best results
• Unsweetened cocoa powder: Gives the muffins rich chocolate flavor. Sift if clumpy and try to use a good quality Dutch-processed cocoa
• Baking powder and baking soda: These work together for that bakery-style rise and fluffy crumb. Check expiration dates so they work properly
• Salt: Brings out chocolate notes and balances sweetness. Use fine sea salt for even distribution
• Espresso powder: Optional but highly recommended because it deepens the chocolate taste without giving a strong coffee flavor. Use fresh espresso powder for best results
• Butter unsalted: Melted for extra richness. Use good quality butter and let it cool slightly before mixing
• Granulated sugar: Adds sweetness and helps with the muffin's tender texture. White sugar is classic here
• Eggs room temperature: These bind everything together and add richness. Let them sit out for 30 minutes or place in warm water for a few minutes to bring to room temperature
• Vanilla extract: Enhances all the other flavors. Use pure vanilla if possible
• Buttermilk room temperature: Adds moisture and tang to create that special muffin crumb. Can substitute with milk plus a teaspoon of vinegar or lemon juice if needed
• Sour cream room temperature: Makes the muffins extra moist and soft. Use full-fat for best texture
• Semi-sweet chocolate chips: Divide these to mix into the batter and for the top. Use a higher-end brand if you can for intense chocolate flavor

Instructions

Preheat and prepare muffin pan:

Set oven to 425 degrees Fahrenheit and line a jumbo muffin pan with large liners. This helps achieve a tall bakery-style rise and keeps muffins from sticking

Mix dry ingredients:

In a bowl whisk together flour cocoa powder baking powder baking soda salt and espresso powder if using. Whisk well so everything is evenly incorporated and there are no clumps

Combine butter and sugar:

In a separate large bowl whisk cooled melted butter and sugar until the mixture looks a bit fluffy and pale. This is the base for a moist muffin

Add wet ingredients:

Add eggs one at a time whisking well after each. Stir in vanilla extract sour cream and buttermilk until the mixture is completely smooth. Make sure these ingredients are at room temperature to avoid a lumpy batter

Combine wet and dry ingredients with chocolate:

Fold the dry mixture into the wet mixture and gently stir in one and a half cups of chocolate chips. The batter will be thick and heavy. Be gentle so you do not overmix. Let this batter rest 10 to 15 minutes so the gluten can settle and the muffins puff up more

Fill muffin pan and add chocolate on top:

Divide the batter evenly among prepared muffin cups. Fill nearly to the top and gently press remaining chocolate chips on top for that signature bakery look

Bake high then low:

Place muffins into the hot oven and bake at 425 degrees Fahrenheit for 5 minutes to get that lift. Lower the oven to 350 degrees Fahrenheit and bake another 19 to 25 minutes until a tester inserted comes out with a few moist crumbs

Cool and enjoy:

Let muffins cool in the pan for several minutes before removing. Enjoy warm or let them cool completely for the best chocolate chip dispersal

My favorite part of these muffins has to be the generous amount of chocolate chips. I have great memories of making a double batch with my younger sister and sneaking the warmest muffin before dinner. The gooey chocolate puddles on top are hard to resist.

Storage Tips

Store cooled muffins in an airtight container for up to four days at room temperature. For longer storage wrap muffins tightly and freeze for up to two months. Warm slightly before serving to restore that bakery fresh texture.

Ingredient Substitutions

If you do not have buttermilk mix regular milk with a teaspoon of lemon juice or white vinegar and let sit for five minutes. Greek yogurt can swap in for sour cream if needed. For a nutty touch try swapping half the chocolate chips with chopped walnuts.

Serving Suggestions

Enjoy these muffins warm from the oven or split and toasted with a bit of butter. They are just as good for breakfast with coffee as they are with a scoop of vanilla ice cream for dessert. If making for a brunch serve alongside fresh strawberries or orange slices for a bright contrast.

Cultural and Historical Context

Costco’s giant muffins are legendary in American warehouse clubs for being both oversized and indulgent. People have been recreating them at home ever since and this version proves you do not need a membership to treat yourself. The combo of cocoa and buttermilk is a classic bakery formula for deep flavor and perfect texture.

Seasonal Adaptations

Add a pinch of warm cinnamon or pumpkin spice for a fall twist. Sprinkle flaked sea salt on the tops before baking for a trendy upgrade. Swap in white chocolate or dark chocolate chips for a holiday look.

Success Stories

A friend once made these for her daughter’s bake sale and they sold out in record time to parents and teachers alike. I have also heard of bakers making minis for snack boxes or mixing sprinkles into the batter for a birthday surprise.

Freezer Meal Conversion

Let baked muffins cool completely then wrap tightly in plastic and place in freezer bags. They thaw quickly at room temperature or you can warm each muffin in the microwave for thirty seconds to bring back that just-baked texture.

Enjoy your bakery-style chocolate muffins at home—each bite is a celebration of chocolate and comfort. Make an extra batch because they disappear fast!

Recipe FAQs

→ What makes these muffins taste like Costco’s?

The mixture of cocoa powder, buttermilk, sour cream, and lots of chocolate chips gives them a rich, moist texture and chocolate intensity similar to the store version.

→ Can I use regular muffin tins?

Yes, use standard liners and fill only two-thirds full. Reduce baking time accordingly and check for doneness sooner.

→ Why start baking at a higher temperature?

Beginning with a higher heat helps the muffins rise quickly, creating that signature domed top before finishing at a lower temperature.

→ Is espresso powder required?

Espresso powder is optional but boosts the chocolate flavor without leaving a coffee taste. Omit it if preferred.

→ How can I keep the muffins moist?

Don't overbake, and use both buttermilk and sour cream as in the method—they help keep the crumb tender and moist.