These S’mores Bars deliver everything you love about campfire s’mores—buttery graham crunch, silky melted chocolate, and a toasted-marshmallow cap—in a tidy 9×13-inch pan that slices cleanly. The base is a shortbread-style graham crust (not crumbly), baked just long enough to set. A generous milk-chocolate layer melts on contact, and a blanket of mini marshmallows toasts to golden peaks under quick, controlled heat. The result is gooey without chaos, with neat edges for lunchboxes, bake sales, or party platters.
Ingredients & Measurements
- Yield: 24 bars (cut 6×4 from a 23×33 cm / 9×13 in pan)
- Nonstick spray and parchment (to line pan with overhang)
- Graham crust: 200 g (2 cups) finely crushed graham cracker crumbs; 115 g (½ cup) unsalted butter, melted; 50 g (¼ cup) granulated sugar; ¼ tsp fine sea salt
- Chocolate layer: 450 g (16 oz) milk chocolate bars or chips (see notes for semisweet blend)
- Marshmallow layer: 400 g (14 oz) mini marshmallows
- Optional finish (choose one): 30 g (¼ cup) crushed graham crumbs for sprinkling; 30 g (¼ cup) mini chocolate chips; 2 Tbsp caramel sauce (drizzle after baking)
Step-by-Step Instructions
- Prep the pan and oven (5 minutes). Heat oven to 175°C / 350°F, rack in the center. Lightly spray a 9×13-inch metal pan. Line with parchment, leaving a 2–3 cm (1-inch) overhang on the long sides for easy lifting; light spray beneath the parchment keeps it from shifting.
- Mix the crust (1–2 minutes). In a bowl, combine 200 g graham crumbs, 115 g melted butter, 50 g sugar, and ¼ tsp salt. Stir until every crumb is glossy and the mixture holds when squeezed. Dry pockets cause a fragile base; it should feel like damp sand.
- Press and pre-bake (10–12 minutes). Tip the crust mixture into the pan. Using a flat-bottom cup, press firmly into an even, compact layer, especially along the corners and edges. Bake 10–12 minutes until the surface looks set and edges begin to deepen in color.
- Melt the chocolate with residual heat (3 minutes). Remove the pan. Immediately scatter 450 g chocolate evenly over the hot crust. Rest 2–3 minutes so the heat softens the chocolate; the pieces should look glossy and start losing definition.
- Smooth the chocolate (30–45 seconds). With an offset spatula, spread the softened chocolate into an even layer from edge to edge. Work quickly and gently to avoid tearing the crust. If a few chips resist, return the pan to the oven 30 seconds to finish softening.
- Top with marshmallows (1 minute). Sprinkle 400 g mini marshmallows in a single, dense layer over the chocolate. Press lightly with a clean hand to seat them so the top bakes as one quilted layer rather than rolling off when sliced.
- Bake to puff (3–4 minutes). Return the pan to 175°C / 350°F for 3–4 minutes until marshmallows are puffed and just beginning to color. This warms the chocolate back to fluid and sets the layers together.
- Brown the top precisely (45–90 seconds). Switch the oven to broil (grill) on high. Broil 45–90 seconds, rotating the pan once, until the marshmallow tops are evenly golden with a few deeper spots. Watch constantly—they go from perfect to too dark in seconds.
- Set the slab (25–35 minutes). Cool the pan on a rack 25–35 minutes until warm but not hot; the chocolate should be soft-set, not liquid. If you plan to slice ultra-neat squares, chill 15–20 minutes more—do not fully refrigerate or the marshmallow can become rubbery.
- Lift and portion cleanly (5–8 minutes). Use the parchment overhang to lift the slab to a board. Oil a large chef’s knife very lightly or spray with nonstick; wipe between cuts. For 24 pieces, cut 6 columns × 4 rows. If marshmallow sticks slightly, warm the knife under hot water, dry well, and continue.
- Finish and hold (optional). Sprinkle a dusting of crushed graham crumbs or mini chips while the top is just tacky, or drizzle thin caramel once bars are cool (caramel runs on warm marshmallow). Rest 10 minutes more to set any toppings.
- Store properly (up to 3 days). Keep bars in a single layer (or with parchment between layers) in an airtight container at cool room temperature for up to 3 days. Avoid the fridge; condensation can weep on the marshmallow and dull the chocolate.
Cooking Notes
- Chocolate choice: Milk chocolate is nostalgic and melts silkier at lower temps; for a less-sweet profile, use 300 g milk + 150 g semisweet. Avoid “baking melts” with stabilizers—they can re-set more firmly and fight slicing.
- Crust stability: A compact press + short prebake prevents a sandy base later. If using store-bought crumb crust mix, weigh to 200 g and add ½–1 Tbsp extra melted butter if it looks dusty.
- Neat cuts, every time: Lightly oil the blade and clean it every 2–3 cuts. Warm water + dry blade helps glide through the marshmallow without tearing the top.
- No blowtorch needed: The bake + brief broil gives a controlled toast. If you don’t have a broiler, bake an extra 3–4 minutes at 190°C / 375°F until marshmallows color; watch closely.
- Outdoor/BBQ variation: Bake the crust on a covered grill at 190°C / 375°F 10–12 minutes (indirect heat). Add chocolate and marshmallows, cover 2–3 minutes until puffed; kiss with direct heat 10–20 seconds for color if your grill allows.
- Mix-ins: Swirl 2 Tbsp peanut butter into the softened chocolate before adding marshmallows, or scatter ½ cup chopped toasted pecans for crunch.
- Allergy & swaps: Use gluten-free graham crumbs for a GF version (crust texture remains excellent). Dairy-free? Use vegan butter and dairy-free milk chocolate; marshmallows must be gelatin-free if needed—check labels.
- Humidity caution: On humid days, marshmallow can turn tacky. Slice, then dust the cut sides lightly with extra fine graham crumbs; it protects edges and improves handling.
- Serving temp: Bars taste best at cool room temperature; too warm and the chocolate slumps, too cold and the marshmallow chews rubbery.
Nutrition Facts (per serving)
- Serving size: 1 bar (1/24 of pan)
- Approximate calories: 240 kcal
- Total fat: 10 g
- Saturated fat: 6 g
- Carbohydrates: 34 g
- Dietary fiber: 1 g
- Total sugars: 23 g
- Protein: 3 g
- Sodium: 140 mg
Conclusion
These S’mores Bars streamline the classic into a professional, party-ready format: a firmly set graham base, a smooth chocolate layer, and a precisely toasted marshmallow top that slices neatly. By prebaking the crust, soft-melting the chocolate, and broiling with eyes-on timing, you’ll get consistent color, clean layers, and gooey center bites—no campfire required. Customize the chocolate mix, add a crunchy sprinkle, and serve at cool room temp for the best texture.
