Copycat Costco Chocolate Chunk Cookies Recipe – Big, Chewy, and Loaded With Chocolate

If you’ve ever walked past the bakery section at Costco and been tempted by those giant, glossy chocolate chunk cookies, you’re in the right place. This copycat version gives you that same bakery-style look and taste at home—chewy centers, crisp edges, and big puddles of melted chocolate. No special equipment or complicated steps.

Just pantry staples, a couple of smart tricks, and a little patience while the dough rests. Bake them big, share them warm, and watch them disappear.

Why This Recipe Works

This recipe leans on a few simple techniques to mimic that signature Costco bakery texture:

• Higher brown sugar ratio: Boosts chewiness, moisture, and deep caramel flavor.
• Cold butter start: Softened but not melted butter helps cookies hold their height and bake up thick.
• Cornstarch and egg yolk: A touch of cornstarch and an extra yolk keep the centers tender and plush.
• Chocolate chunks, not chips: Chunks melt into wide, glossy pockets like bakery cookies.
• Chill time: Resting the dough develops flavor and prevents excessive spreading.

What You’ll Need

• 2 1/2 cups (315 g) all-purpose flour
• 1 tablespoon cornstarch
• 1 teaspoon baking soda
• 1/2 teaspoon baking powder
• 3/4 teaspoon fine sea salt
• 3/4 cup (170 g) unsalted butter, softened but cool (about 65–68°F)
• 1 cup (200 g) packed light brown sugar
• 1/2 cup (100 g) granulated sugar
• 1 large egg + 1 large egg yolk, room temperature
• 2 teaspoons pure vanilla extract
• 12 oz (340 g) semisweet chocolate chunks (or chop a bar for varied sizes)
• Optional: 1/2 cup (60 g) toasted chopped walnuts or pecans
• Finishing: Flaky sea salt for sprinkling

Instructions

1. Prep your pans: Line two large baking sheets with parchment paper. Set aside.For best results, use light-colored sheets to prevent over-browning.
2. Whisk the dry ingredients: In a medium bowl, whisk flour, cornstarch, baking soda, baking powder, and salt until blended.
3. Cream the butter and sugars: In a large bowl, beat the softened butter, brown sugar, and granulated sugar on medium speed for 2–3 minutes until slightly fluffy and creamy. Don’t whip until airy; you want some density for thick cookies.
4. Add eggs and vanilla: Beat in the egg, then the yolk, followed by the vanilla. Mix just until smooth and glossy.
5. Combine wet and dry: Add the dry ingredients to the wet in two additions.Mix on low until almost combined, with a few flour streaks remaining.
6. Fold in chocolate (and nuts if using): Use a spatula to fold in the chocolate chunks and optional nuts. Stop as soon as everything is evenly distributed.
7. Chill the dough: Cover and refrigerate for at least 2 hours—ideally 12–24 hours for best flavor and structure. If you’re short on time, chill formed dough balls for 45–60 minutes.
8. Preheat and portion: Heat your oven to 350°F (175°C).Scoop large portions—about 3 tablespoons (80–90 g) each—to get that bakery size. Roll into tall mounds rather than smooth balls for thicker centers.
9. Top with extra chunks: Press a few extra chocolate pieces on top of each dough mound so you get visible pools after baking.
10. Bake: Place 6–8 cookies per sheet. Bake for 11–14 minutes until edges are set and golden, tops are lightly cracked, and centers still look a touch underdone. Rotate pans halfway for even color.
11. Finish and set: Immediately sprinkle with a pinch of flaky sea salt. Cool on the sheet for 8–10 minutes to set the centers, then transfer to a rack to finish cooling.
12. Serve warm: These are best slightly warm when the chocolate is glossy and soft.

Storage Instructions

• Room temperature: Store cooled cookies in an airtight container for 3–4 days. Tuck in a slice of bread to keep them soft.
• Freezing baked cookies: Freeze in a single layer, then bag for up to 2 months.Rewarm at 300°F (150°C) for 5–7 minutes.
• Freezing dough balls: Scoop, then freeze on a sheet pan. Transfer to a freezer bag for up to 2 months. Bake from frozen at 350°F, adding 1–2 minutes to the time.

Why This is Good for You

No, this isn’t a “health” cookie.

But there are still a few positives. Real butter and quality chocolate give you big flavor, so smaller portions can still feel satisfying. Making them at home lets you control ingredients—no preservatives, and you can choose fair-trade chocolate or reduce sugar slightly. Sharing a batch can also turn dessert into a social treat rather than a solo snack, which naturally encourages balance.

Common Mistakes to Avoid

• Overmixing the dough: Tough cookies happen when gluten develops too much.Mix just until combined.
• Skipping the chill: Warm dough spreads too far and bakes thin. Chill time equals thick, chewy cookies.
• Overbaking: Pull them when the centers still look a bit soft. They’ll finish setting on the pan.
• Using all chips: Chips hold shape; chunks melt into puddles.Use at least half chunks or chopped bars for the bakery look.
• Hot pans for second batch: Hot sheets make cookies spread. Cool pans between batches.
• Butter too warm: Very soft or melted butter leads to flat cookies. Aim for cool-room-temp butter.

Alternatives

• Different chocolates: Mix semisweet and dark chunks, or add a handful of milk chocolate for sweetness.
• Brown butter: For a nutty depth, brown the butter, cool until just firm, then cream as directed.Expect a touch more spread.
• Gluten-free: Use a 1:1 gluten-free all-purpose blend with xanthan gum. Add 1 extra teaspoon of milk if dough seems dry.
• Dairy-free: Swap butter for a high-fat vegan butter stick and use dairy-free chocolate. Chill well to reduce spread.
• Less sweet: Reduce granulated sugar by 2 tablespoons and increase salt to a full 1 teaspoon.
• Nutty version: Toasted walnuts or pecans bring crunch and balance the sweetness.

FAQ

Can I make these smaller?

Yes.

Scoop 2-tablespoon portions and bake 9–11 minutes. They’ll be less thick, so keep an eye on them and pull early to keep the centers chewy.

Do I have to chill the dough overnight?

No, but it helps a lot. Two hours is the minimum.

Overnight gives deeper flavor and a more controlled spread, closer to that bakery-style texture.

What chocolate is closest to the Costco style?

Use semisweet chunks or roughly chopped semisweet bars. Mixing in a few larger pieces creates those big melted pockets on top.

Why add cornstarch?

Cornstarch softens the crumb and helps keep the centers thick and tender without making the cookies cakey.

My cookies spread too much—what went wrong?

Likely warm butter, insufficient chilling, or too little flour. Make sure your butter is cool, chill dough thoroughly, and weigh your flour for accuracy.

Can I freeze the dough and bake later?

Absolutely.

Portion the dough, freeze solid, then store in a bag. Bake from frozen, adding a minute or two, and top with a couple of extra chunks before baking.

How do I get shiny, glossy chocolate on top?

Press a few chocolate chunks onto each dough ball just before baking. They’ll melt on the surface and set with that glossy bakery look.

Can I use dark brown sugar?

Yes.

It adds more molasses flavor and extra moisture. The cookies may bake slightly darker and taste a bit richer.

What if I don’t have cornstarch?

Skip it and add an extra tablespoon of flour. The texture will be slightly less plush but still delicious.

How do I know when they’re done?

Edges should be golden and set, and the centers should look soft and a little pale.

Light cracking on top is a good sign. They’ll firm up as they cool on the sheet.

Final Thoughts

These copycat Costco chocolate chunk cookies bring the best part of the bakery case straight to your kitchen. With a short chill, big scoops, and real chocolate chunks, you’ll get thick, chewy cookies that feel truly special.

Keep a bag of frozen dough balls on hand for last-minute guests or weeknight cravings. Bake them big, salt the tops, and enjoy them warm—no membership required.