Copycat Trader Joe’s Peppermint S’mores Cake Recipe

If you’ve ever stood in a Trader Joe’s aisle mid-December, clutching that shiny red box of Chocolate Peppermint Loaf Mix like it was the last golden ticket to winter happiness, then you know the exact vibe this Peppermint S’mores Cake is chasing. It’s campfire comfort meets peppermint wonderland. Marshmallows, chocolate, graham, all bundled into one square of festive joy.

The first time I made this, it was just after a snowstorm had dusted our backyard, and my nephews were over, still bundled in hats they refused to take off. We cranked up the oven, layered the pan, and watched the marshmallows puff and toast under the broiler like little clouds catching firelight. When we cut into it, sticky, rich, pepperminty, someone said, “It’s like a s’mores but with a Christmas sweater.” Pretty much nailed it.

This copycat Trader Joe’s Peppermint S’mores Cake tastes just like the one made from their Chocolate Peppermint Loaf & Baking Mix, but you can make it anytime, from scratch, no seasonal box needed. It’s chewy, fudgy, toasty, with that just-right peppermint note that makes it feel like winter even if it’s 70° and sunny.

How to Make Peppermint S’mores Cake

Start with a buttery graham cracker crust pressed into the bottom of a square pan. Bake it just long enough to set, think golden, a little sandy, and smelling like campfire memories.

Next, whip up a rich peppermint-chocolate batter with cocoa, chocolate chips, and just a whisper of mint. Pour it right over the crust and bake until set but still fudgy in the middle. You’re aiming for that brownie-meets-loaf texture.

While it’s still hot, scatter mini marshmallows all over the top. Slide it under the broiler for a quick toast, watch close, it goes from perfect to burnt fast. Those marshmallows puff, bronze, and melt into a gooey, pull-apart topping.

Let it cool a bit so the sticky top sets. Then slice into squares and serve warm, melty, and full of holiday magic.

Nutrition (per 1 square, based on 9 servings)

Calories: 390
Fat: 20g
Saturated Fat: 10g
Carbohydrates: 48g
Sugar: 35g
Protein: 4g
Fiber: 2g

Cooking Times

• Prep Time: 20 minutes
  (includes crust, batter, and layering)
• Bake Time: 24–28 minutes
  (at 350°F for the cake layer after pre-baking the crust)
• Crust Pre-Bake: 8 minutes
  (to set the graham base before adding batter)
• Broil Time: 30–60 seconds
  (to toast marshmallows—watch closely!)
• Cooling Time: 15–20 minutes
  (to allow the marshmallow top to set before slicing)

Ingredients (for one 8×8 pan, 9 generous bars)

Graham Crust

• 1 cup crushed cinnamon graham crackers (about 8 sheets)
• 3 tablespoons granulated sugar
• 6 tablespoons unsalted butter, melted
• Pinch of sea salt

Peppermint Chocolate Cake

• ¾ cup all-purpose flour
• ¼ cup Dutch-process cocoa powder
• 1 tablespoon cornstarch
• ½ teaspoon baking soda
• ¼ teaspoon salt
• ½ cup granulated sugar
• ¼ cup packed brown sugar
• ½ cup vegetable oil
• ¼ cup sour cream (or plain yogurt)
• 2 large eggs
• 1 teaspoon vanilla extract
• ½ teaspoon peppermint extract (not more!)
• ⅔ cup semisweet chocolate chips

Marshmallow Top

• 2½ cups mini marshmallows (enough to fully cover the cake)

Tools You’ll Need

• 8×8-inch square baking pan
• Mixing bowls
• Hand mixer or whisk
• Spatula
• Parchment paper
• Oven + broiler

Instructions

1. Make the graham crust

Preheat oven to 350°F (175°C). Line your pan with parchment.
Stir together graham crumbs, sugar, salt, and melted butter. Press into bottom of pan to form an even crust. Bake 8 minutes until just golden. Let it cool slightly while you prep the batter.

2. Make the peppermint chocolate cake

In a medium bowl, whisk flour, cocoa, cornstarch, baking soda, and salt.
In a large bowl, beat together oil, sour cream, both sugars, eggs, vanilla, and peppermint extract until smooth. Fold in dry ingredients until just combined. Stir in chocolate chips.
Pour over cooled crust and spread evenly.

3. Bake the cake

Bake at 350°F for 24–28 minutes or until center is just set and a toothpick comes out with moist crumbs. Do not overbake, it should feel like brownie-meets-loaf texture.

4. Top with marshmallows and broil

Remove from oven, immediately scatter marshmallows on top. Switch oven to broil. Broil for 30–60 seconds, watching constantly, until marshmallows puff and brown. Pull it the second they’re golden, seconds matter here.

5. Cool and slice

Let it cool at least 15–20 minutes to let the marshmallows set. Slice into 9 squares with a buttered knife. Serve slightly warm for gooey magic or chill slightly for neater squares.

Tips

• Use Dutch cocoa for deep chocolate flavor, don’t swap in natural cocoa.
• Don’t go heavy on the peppermint extract. A little goes a long way.
• Lightly grease the knife before slicing to avoid sticky marshmallow pull.
• Want it extra gooey? Add a few chocolate chunks under the marshmallows before broiling.

What to Serve With

Wintery Sweet Pairings

• Hot cocoa with crushed candy canes – Over-the-top? Maybe. Perfect with this cake? Absolutely.
• Fresh orange slices – Bright citrus helps cut through the richness and echoes that holiday theme.
• Peppermint tea – Soothing, clean, and a gentle way to balance the decadence.

Snacky Comfort

• Sea salt kettle chips – Sounds weird until you try it. Salty crunch + chocolate = genius.
• Toasted pecans – Add a nutty, roasty contrast to the chewy sweet cake.
• Pretzel sticks dipped in dark chocolate – For bonus crunch and sweet-salty delight.

If You’re Going Full Dessert Table

• Mini cheesecakes or cheesecake dip – Creaminess pairs beautifully with the toasted marshmallow top.
• White chocolate bark with dried cranberries – Keeps the peppermint-holiday vibe going but adds fruity brightness.
• A scoop of peppermint or vanilla ice cream – Because sometimes one dessert needs a friend.

Variations

Candy Cane Crunch Version

Add ¼ cup crushed peppermint candies on top of the marshmallows right after broiling. Adds crunch and a stronger minty punch.

Mocha S’mores Cake

Replace ¼ cup of the sour cream with strong brewed coffee. It deepens the chocolate and adds a mocha edge.

No-Graham Shortcut

Use crushed chocolate wafers or even plain digestive biscuits if you can’t find cinnamon grahams. Still works beautifully.

Cake Mix Hack

In a rush? Use chocolate cake mix (not fudge brownie mix) and add ½ teaspoon peppermint extract. It’s not exactly Trader Joe’s, but it’s still a winter crowd-pleaser.

S’mores Cake Bars

Bake in a 9×13 pan and double the recipe for parties. Cut into 18 small bars. Works like a charm for cookie swaps or bake sales.

Ingredient Substitutes

Cinnamon Graham Crackers

If you can’t get your hands on cinnamon graham crackers (Trader Joe’s or Nabisco both work great), you can swap in regular graham crackers with a dash of cinnamon stirred into the crumbs. Chocolate graham crackers work too for a deeper, more dessert-like base. Digestive biscuits with a sprinkle of cinnamon sugar also give a lovely texture and flavor if you’re outside the US.

Dutch-Process Cocoa

Dutch cocoa gives that smooth, dark chocolate flavor that makes this cake feel richer than your average mix. If you don’t have Dutch-process, you can use natural cocoa powder, but be aware it’s more acidic and might slightly alter the texture and rise. If you do make the swap, add an extra ¼ teaspoon of baking soda to keep things balanced. Black cocoa is another fun option for an even deeper color and dramatic look.

Sour Cream

Sour cream keeps the crumb tender and adds a touch of tang that helps balance the sweetness. If you don’t have it, plain full-fat Greek yogurt is a near-perfect stand-in. You can also use buttermilk (reduce the total liquid slightly), or even full-fat coconut yogurt for a dairy-free version.

Peppermint Extract

Peppermint extract is what gives this cake its holiday personality. Be gentle with it, ½ teaspoon goes a long way. If you don’t have any extract, crushed peppermint candies (about ¼ cup melted into the batter) can give a similar effect. You could also use a tiny bit of peppermint essential oil, but be super cautious, start with 1–2 drops, no more.

Mini Marshmallows

Mini marshmallows give that classic s’mores look and texture, but you’ve got options. If you only have the large ones, just snip them in half with kitchen scissors and scatter them across the top. You could also swirl in a layer of marshmallow fluff if you want something gooier and more molten. For a fancy twist, homemade marshmallow topping or torched meringue adds an artisanal touch.

Chocolate Chips

Semisweet chocolate chips are what Trader Joe’s uses in their mix, but you can absolutely play around here. Milk chocolate chips will make it sweeter and more classic s’mores-like. Chopped dark chocolate gives it a bit more depth. You could even use white chocolate chips if you want contrast, or toss in some peppermint chips to double down on the minty cheer.

Honest Review

After a few batches (and a few too many “test bites”), I can honestly say this version captures the spirit of Trader Joe’s Peppermint S’mores Cake beautifully. The cake itself is rich and deeply chocolatey, almost brownie-like, with just the right amount of peppermint, cool, festive, but never overpowering. That’s a hard balance to nail, but this one does.

The graham crust gives it that nostalgic s’mores crunch, and once you hit the gooey marshmallow top? Pure winter dessert magic. Broiling the marshmallows adds that golden crackle you can’t fake, and when it’s all still warm and melty… yeah, it hits hard.

Is it exactly like Trader Joe’s version made with their mix? Not precisely. The texture is a bit more luxe, the peppermint slightly brighter, and the chocolate flavor might actually be better. TJ’s probably builds theirs to last on shelves and ship across states, but this one? It’s meant to be eaten fresh, shared in a cozy kitchen, and maybe not saved for tomorrow.

If you’re craving that marshmallow-graham-chocolate comfort with a peppermint twist, this copycat absolutely delivers. It’s festive, indulgent, and way too easy to go back for a second square. Maybe a third.

FAQ

1. What is Trader Joe’s Peppermint S’mores Cake?
It’s a holiday dessert made with a rich peppermint chocolate cake base, a graham cracker crust, and a toasted marshmallow topping. It’s like a winter twist on classic s’mores.

2. Can I make Peppermint S’mores Cake without the Trader Joe’s mix?
Yes! This copycat recipe uses pantry ingredients to recreate the flavor and texture of the TJ version, no boxed mix needed.

3. What kind of cocoa should I use for this recipe?
Use Dutch-process cocoa for a deep, smooth chocolate flavor. Natural cocoa works in a pinch, but Dutch-style is closer to the original.

4. How much peppermint extract should I use?
Use about ½ teaspoon of peppermint extract. It’s strong, so a little goes a long way. Don’t overdo it or it’ll taste like mouthwash.

5. Can I make this cake dairy-free?
Yes! You can use coconut yogurt instead of sour cream, and swap in dairy-free chocolate chips, butter, and marshmallows.

6. Do I need to toast the marshmallows on top?
Yes, toasting them gives that gooey, golden s’mores feel. Use your oven’s broiler for 30 to 60 seconds and watch closely.

7. What size pan should I use?
An 8×8-inch square baking pan works best. It gives you thick, brownie-like squares with the right cake-to-crust ratio.

8. How do I keep the marshmallow topping from sticking to the knife when slicing?
Let the cake cool for 15–20 minutes, then use a buttered knife to slice. That helps the sticky marshmallow top cut cleanly.