These homemade Costco-style chocolate muffins are rich, moist, and loaded with deep chocolate flavor. With a tender crumb and melty chocolate chips throughout, they truly rival the iconic bakery originals. I love making these indulgent muffins at home—they're perfect for breakfast, dessert, or an anytime chocolate fix.

Why You’ll Love This Recipe

I love this recipe because it perfectly captures the decadent, oversized muffins I find at Costco. The texture is soft and moist, thanks to sour cream and a mix of cocoa powder and chocolate chips. It uses simple ingredients I likely already have in my pantry, and the results are always bakery-worthy. Plus, making them at home means I can enjoy these jumbo chocolate muffins fresh and warm.

Ingredients

(Here's a tip: Check out the full list of ingredients and measurements in the recipe card below.)

all-purpose flour
baking powder
baking soda
kosher salt
unsweetened cocoa powder
hot water
granulated sugar
vegetable oil
large eggs
pure vanilla extract
sour cream
semi-sweet chocolate chips

Directions

I preheat my oven to 375°F and line a 6-cup jumbo muffin pan with liners or lightly grease them.
In a small bowl, I whisk together ¼ cup of cocoa powder with the hot water until smooth, then let it cool.
In another bowl, I mix the flour, remaining cocoa powder, baking powder, baking soda, and salt.
In a large bowl, I whisk together the sugar, oil, eggs, and vanilla until smooth.
I add the sour cream and the cooled cocoa mixture to the wet ingredients and stir until combined.
Gradually, I mix in the dry ingredients, being careful not to overmix.
I fold in most of the chocolate chips, reserving some for the tops.
I divide the batter evenly into the muffin cups and sprinkle the remaining chips on top.
I bake them for 25–30 minutes or until a toothpick comes out clean.
I let them cool in the pan for 5 minutes before transferring to a wire rack.

Servings and Timing

Servings: 6 jumbo muffins
Prep Time: 15 minutes
Cook Time: 25–30 minutes
Total Time: 40–45 minutes

Variations

I sometimes make standard-sized muffins instead of jumbo ones—this yields about 12 muffins and they bake in 18–22 minutes.
For a deeper chocolate flavor, I add a teaspoon of espresso powder to the batter.
If I want a nutty crunch, I toss in a handful of chopped walnuts or pecans.
Swapping in dark chocolate or white chocolate chips gives a fun twist.
When I’m out of sour cream, full-fat Greek yogurt works well too.

Storage/Reheating

I store these muffins in an airtight container at room temperature for up to 3 days.
In the fridge, they last up to a week, and I just warm them before serving.
To freeze, I wrap each muffin individually and store them in a freezer-safe bag for up to 3 months.
When reheating, I microwave a thawed muffin for 20–30 seconds to bring back the fresh-baked feel.

FAQs

Can I make these with standard muffin tins?

Yes, I often use a 12-cup muffin tin instead. I just reduce the baking time to around 18–22 minutes.

What’s the secret to making them taste like Costco’s?

Using both cocoa powder and real chocolate chips, along with sour cream, gives them that rich, moist texture that tastes just like the ones from the bakery.

Can I freeze these muffins?

Absolutely. I wrap each one in plastic wrap and store them in the freezer for up to 3 months. They reheat beautifully.

Why do I need to bloom the cocoa in hot water?

Blooming enhances the chocolate flavor. Mixing cocoa with hot water releases its richness, giving the muffins a deeper taste.

Do I have to use sour cream?

Sour cream is ideal for moisture and tenderness, but I sometimes use full-fat Greek yogurt when I need a substitute.

Conclusion

These copycat Costco chocolate muffins hit all the right notes—rich, moist, deeply chocolaty, and perfectly oversized. I love how easy they are to make at home and how they satisfy my sweet tooth every time. Whether I serve them for breakfast or dessert, these muffins always disappear fast.