This festive treat began as a way to turn pantry staples into something special for holiday gatherings. I first made these bars one December when I needed a last-minute contribution to a cookie exchange and only had a handful of ingredients on hand. The combination of a buttery graham crust, sweetened condensed milk, pillowy mini marshmallows and melted chocolate chips created a texture contrast—crisp base, chewy center and glossy chocolate topping—that had everyone asking for the recipe. Since then, these bars have become my go-to for holiday plates and school bake sales because they travel well and please both kids and adults.

What makes these bars memorable is the balance of textures and the ease of assembly. The graham crumb base, lightly enriched with melted butter and a touch of cocoa for depth, bakes to a slightly crisp foundation. Pouring warm sweetened condensed milk over that base and topping with marshmallows and chocolate chips creates a soft, chewy layer after a short bake. The result is indulgent but simple—no tempering chocolate or special equipment required. They’re adaptable for dietary needs, easy to scale, and they store and freeze beautifully, which makes them ideal for holiday prep.

Ingredients

• 2 cups graham cracker crumbs: About 12 to 14 full sheets crushed; Honey Maid or store-brand whole graham crackers work well. The crumbs form a sweet, crunchy base—pulse in a food processor for the best texture.
• 1/4 cup unsweetened cocoa powder: Adds chocolate depth to the crust; choose a high-quality natural or Dutch-processed cocoa depending on preference. I use a Dutch-processed for a rounder, less acidic flavor.
• 1 1/2 cups powdered sugar: Fine grind sugar smooths the base and balances cocoa bitterness; sift if lumpy for an ultra-fine texture.
• 3/4 cup unsalted butter, melted: Melt and cool slightly before mixing. For dairy-free versions, use 3/4 cup melted coconut oil rather than butter—this will yield a slightly different mouthfeel but similar structure.
• 1 can (14 oz) sweetened condensed milk: The secret to the chewy, caramel-like middle layer; use standard brands like Eagle Brand for consistent sweetness and viscosity.
• 3 cups mini marshmallows: Mini marshmallows distribute evenly across the surface and puff lightly in the oven; use classic marshmallows rather than gelatin-free if not avoiding gelatin.
• 1 1/2 cups chocolate chips: Dark, semisweet or milk chocolate all work—pick one based on how sweet you want the final bars. Chop larger pieces if you want pockets of melted chocolate.
• 1/2 cup chopped nuts (optional): Toasted walnuts or pecans add crunch; omit for nut-free trays. Toast in a dry skillet for 3–5 minutes to boost flavor.

Instructions

Prepare the oven and pan: Preheat the oven to 350°F (177°C). Line a 9x13-inch (23x33 cm) baking pan with parchment paper, leaving an overhang to lift the bars out easily. Greasing lightly helps parchment adhere and ensures clean removal. Make the base: Combine 2 cups graham cracker crumbs, 1/4 cup unsweetened cocoa powder and 1 1/2 cups powdered sugar in a large bowl. Pour in 3/4 cup melted unsalted butter and stir until the mixture holds together when pressed. Press firmly and evenly into the prepared pan—use a flat-bottomed measuring cup for consistent density. Bake 8–10 minutes until the edges are fragrant and set; this pre-bake prevents a soggy bottom. Add condensed milk and toppings: Remove the crust from the oven and immediately pour the 14 oz can of sweetened condensed milk over the warm crust, spreading gently with a spatula to cover evenly. Sprinkle 3 cups mini marshmallows across the surface, then scatter 1 1/2 cups chocolate chips on top. If using 1/2 cup chopped nuts, sprinkle them now for toasted crunch. Finish baking: Return the pan to the oven for 2–4 minutes—just long enough for marshmallows to puff and the chocolate to begin softening. Watch closely: marshmallows brown quickly. As an alternative, use the oven broiler on low for 30–60 seconds to toast marshmallow tops, keeping the door ajar and staying vigilant to prevent burning. Cool and set: Remove from oven and let the pan cool on a wire rack for 30 minutes, then chill in the refrigerator for at least 2 hours to fully set and make slicing clean. Use the parchment overhang to lift the slab from the pan and slice into 12–16 bars with a sharp knife. For paper-clean slices, wipe the knife between cuts.

Storage Tips

Store cooled bars in an airtight container in the refrigerator for up to 5 days. Place parchment between layers to prevent sticking. For longer storage, freeze individual bars wrapped tightly in plastic wrap and aluminum foil; thaw in the refrigerator overnight before serving. To revive a slightly chewy, chilled bar, bring it to room temperature for 20–30 minutes—this softens the chocolate and marshmallow without making the crust soggy.

Ingredient Substitutions

For dairy-free versions, replace unsalted butter with an equal amount of melted coconut oil and choose dairy-free chocolate chips plus a vegan sweetened condensed milk alternative or a homemade condensed milk made from coconut milk and sugar reduced to a syrupy consistency. For a gluten-free option, use gluten-free graham-style crumbs or crushed gluten-free shortbread. Reducing powdered sugar in the crust will change texture; keep at least 1 cup to maintain structure. Use chopped peppermint for a holiday mint twist, swapping half the chocolate chips for white chocolate.

Serving Suggestions

Cut into small squares and arrange on a festive platter with sprigs of rosemary or edible glitter for holiday presentation. Pair with strong coffee or mulled cider to balance sweetness. For a party dessert buffet, serve alongside cookies, spiced nuts and fruit preserves so guests can choose contrasting flavors. Garnish bars with a sprinkle of flaky sea salt before chilling for a sophisticated sweet-salty finish.

Cultural Background

These layered bars draw inspiration from classic American pan desserts and holiday tray bakes—think of them as a mash-up between graham-based pie crusts and gooey rocky road-style confections. Layers of crackers or cookies topped with sweet condensed milk and marshmallows are a popular, no-fuss treat in many home kitchens during festive seasons, where portability and make-ahead convenience are prized.

Seasonal Adaptations

Turn bars into a Christmas centerpiece by adding red and green sprinkles, crushed candy canes or chopped dried cranberries on top before chilling. For winter gatherings, fold in toasted pecans and use dark chocolate chips for a richer profile; in summer, lighten with milk chocolate and unsweetened shredded coconut for a tropical twist. Adjust marshmallow quantity to control chewiness—more marshmallows equals a softer top layer.

Meal Prep Tips

Assemble and bake multiple pans, then cool and freeze stacked bars between parchment layers. Label with dates and reheat gently in a low oven (275°F) for 8–10 minutes to refresh the texture. When prepping for an event, slice chilled bars the day before and keep in a single layer in the refrigerator; this prevents sweating and keeps edges neat for presentation.

Success Stories

Readers and friends often tell me these are the first treat to vanish from a dessert table. One neighbor made three batches—one for neighbors, one for co-workers and one for the family—and reported that everyone requested the neighbor batch as gifts. At a recent school fundraiser, individually wrapped bars sold out first, and volunteers asked for the recipe to make more for next year.

These bars are a holiday staple for good reason: they’re simple, adaptable and delightfully nostalgic. Whether you keep them classic or dress them up with nuts and peppermint, they’re an easy way to add homemade charm to any celebration—give them a try and make the recipe your own this season.