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Costco Copycat Muffin Recipe
Ash Tyrrell

Costco Copycat Muffin Recipe

I still remember the first time I tried to recreate those giant, bakery-style muffins from Costco in my own kitchen. I didn't have a fancy trick up my sleeve, just a box of cake mix and a few pantry staples I already had on hand.
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Prep Time 10 minutes
Cook Time 20 minutes
Ingredients Method Notes

Ingredients
  

  • 1 box 18 oz cake mix, any flavor – this is your flavor base, so pick one that matches the muffin you're craving
  • 2 tablespoons all-purpose flour – helps thicken the batter so it holds that tall domed muffin shape
  • 3 large eggs – gives the muffins structure and that soft cakey crumb
  • 2/3 cup milk – keeps the batter moist without making it too thin
  • 1/3 cup vegetable oil – adds richness and keeps the muffins soft for days
  • 1 teaspoon baking powder – gives an extra lift so your muffins puff up big like the bakery version

Method
 

  1. I always start by turning my oven to 375°F so it's fully heated by the time my batter is ready. While it warms up, I line my muffin tin with paper liners or give it a light spray of nonstick cooking spray. This little step saves me from any stuck-muffin disasters later.
  2. In a large bowl, I add the cake mix, flour, eggs, milk, oil, and baking powder all together. I whisk everything until it's smooth and no dry streaks remain, but I try not to overmix since that can make the muffins dense instead of fluffy.
  3. If I'm making a flavor variation like chocolate chip or blueberry, this is when I fold them in gently. I use a spatula instead of the whisk so the add-ins stay whole and don't get crushed into the batter.
  4. I use my ice cream scoop to fill each muffin cup almost all the way to the top. Costco muffins are known for their generous size, so I don't hold back on the batter like I would with a regular muffin recipe.
  5. I slide the tray into the oven and bake for about 20 minutes, checking at the 18-minute mark. I look for lightly golden tops and a toothpick that comes out clean or with just a few moist crumbs.
  6. Once they're out of the oven, I let the muffins sit in the tin for about 5 minutes before moving them to a cooling rack. This little rest helps them firm up so they don't fall apart when I lift them out.

Notes

  • I always use room-temperature eggs and milk since they blend into the batter more evenly.
  • I toss my berries or chocolate chips in a spoonful of flour before folding them in, which stops them from sinking to the bottom.
  • I fill my muffin cups generously because that's what gives them the tall, bakery-style dome.
  • I bake one test muffin first if I'm trying a new flavor combo, just to check the timing before committing the whole batch.
  • I let my muffins cool completely before storing them, or they turn soggy from trapped steam.