This holiday favorite is pure nostalgia on a baking sheet. I first made these bars the winter I hosted my first small family gathering as a new homeowner. I wanted a treat that tasted indulgent but assembled quickly, and the moment the oven door opened and the kitchen filled with warm caramel and chocolate aromas, I knew I had a keeper. The finished bars combine a crisp, buttery graham base with a glossy, sweet condensed milk layer holding pockets of chocolate and butterscotch, toasted pecans, and festive red-and-green M&Ms that make them impossible not to reach for.

They are sweet but balanced by the crunchy crust and toasted nuts. The shredded coconut adds a chewy contrast when you include it, and the butterscotch chips give a mellow, caramel-like warmth beneath the bright chocolate. These bars are ideal for cookie exchanges, school holiday parties, or as a tray of portable cheer to bring to neighbors. I keep a can of sweetened condensed milk on standby each December because this recipe is one of those predictable, dependable hits that people ask about long after the plates are cleared.

Ingredients

• Graham cracker crumbs (2 cups): Use full-sheet graham crackers crushed in a food processor or placed in a sealed bag and pulsed with a rolling pin; this yields about 2 cups and makes a sturdy, slightly sweet crust.
• Unsalted butter (1/2 cup / 115 g), melted: Butter adds richness and helps the crumbs bind; use unsalted so you control the salt level and avoid an overly salty finish.
• Sweetened condensed milk (1 can, 14 ounces): This is the glue that creates the glossy, caramelized top — choose a trusted brand like Eagle Brand for consistent sweetness and texture.
• Semi-sweet chocolate chips (1 cup): Toll House or a similar brand works well; the bittersweet contrast cuts the condensed milk’s sweetness without being bitter.
• Butterscotch chips (1 cup): These add a warm, caramel note; if unavailable, brown sugar chips or white chocolate chips are fine alternatives.
• Sweetened shredded coconut (1 cup, optional): Provides chew and tropical flavor; use sweetened for contrast with the salty nuts, but unsweetened is okay if you want less sugar.
• Chopped pecans (1/2 cup), toasted: Toasting intensifies aroma and crunch; chop fairly small so every bite has a bit of nut without large chunks that impede slicing.
• M&Ms (1/2 cup), red and green: Festive color and a candy crunch; miniature or regular both work — choose your decorative preference.
• Fine salt (a pinch): A tiny pinch in the crust or over the top heightens flavor and balances sweetness.

Instructions

Preheat and prepare the pan: Set the oven to 350 degrees F (175 degrees C). Line a 9 by 13-inch pan with parchment paper, leaving at least a 1-inch overhang on the long sides; this makes lifting the chilled bars out effortless. Grease the parchment lightly if you like. Make the crust: In a medium bowl combine 2 cups graham cracker crumbs and 1/2 cup (115 g) melted unsalted butter with a pinch of fine salt. Stir until the mixture resembles damp sand; the crumbs should hold together when pressed. Press firmly and evenly into the bottom of the prepared pan using the back of a measuring cup or your fingers for an even base. Chill in the refrigerator for 5 minutes to set the butter. Add the condensed milk layer: Open a 14-ounce can of sweetened condensed milk and pour it slowly and evenly over the chilled crust, tilting the pan so the milk reaches corners; the layer should be thin but complete. This will caramelize slightly in the oven and act as an adhesive for the toppings. Top with chips and mix-ins: Evenly sprinkle 1 cup semi-sweet chocolate chips and 1 cup butterscotch chips across the condensed milk layer. Scatter 1 cup sweetened shredded coconut (optional), 1/2 cup toasted chopped pecans, and 1/2 cup red-and-green M&Ms on top. Press the toppings down gently with your palms so they make contact with the condensed milk and will stick after baking. Bake until set: Place the pan in the preheated oven and bake for 18 to 22 minutes. You are looking for golden edges and a center that is gently bubbling; the chips on top may soften and meld into the milk. Avoid overbaking because the bars will continue to set as they cool and you want a slightly chewy interior. Cool and chill for clean slices: Remove from the oven and allow the pan to cool on a wire rack for about 30 minutes. Transfer the pan to the refrigerator and chill for 1 to 2 hours until firm. Use the parchment overhang to lift the slab from the pan and slice into 16 squares with a sharp knife — wiping the knife between cuts yields cleaner edges.

Storage Tips

Store the cooled and sliced squares in an airtight container at room temperature for up to 3 days if you plan to serve soon. For longer storage refrigerate for up to 2 weeks; bring to room temperature for 20 to 30 minutes before serving to soften the chocolate slightly. For freezing, arrange squares in single layers separated by parchment and freeze in an airtight container for up to 3 months. Thaw in the refrigerator overnight to minimize condensation and preserve crispness of the crust.

Ingredient Substitutions

Swap the semi-sweet chocolate chips for dark chocolate chips for more depth, or use milk chocolate for a sweeter bar. If butterscotch chips aren’t available, brown sugar chips or white chocolate chips mixed with a teaspoon of molasses mimic the butterscotch profile. Replace pecans with walnuts or almonds; for a nut-free version use toasted sunflower seeds. To make them kosher for those avoiding dairy, use dairy-free butters and a non-dairy condensed milk alternative, though texture and flavor will shift slightly.

Serving Suggestions

Serve squares on a festive platter with sprigs of rosemary or dust a few with powdered sugar for snowy effect. Pair with robust coffee, spiced tea, or a glass of cold milk. For a holiday cookie plate, mix these bars with shortbread cookies and spiced biscotti to balance textures. They also travel well to potlucks and can be part of a dessert board alongside nuts, dried fruits, and candies.

Seasonal Adaptations

For winter holidays keep the red and green M&Ms. For autumn parties swap the candies for orange M&Ms and replace coconut with toasted pepitas for seasonal color. In spring, use pastel candies and fresh citrus zest in the crust for brightness. You can also fold crushed peppermint into the top layer after baking but before chilling for a classic mint-chocolate contrast.

Meal Prep Tips

Prepare the crust and pre-measure toppings the day before to speed assembly: keep chips, nuts, and candies in separate labeled bowls. Assemble and bake the day you plan to serve for the freshest chew and shine. If making ahead for travel, chill overnight, slice the morning of the event, and layer with parchment to prevent sticking. Use a warmed knife to slice — run the blade under hot water, dry, then cut for cleaner edges.

These bars are an easy way to make the holidays feel special without elaborate baking. They reward a few thoughtful steps — firmly pressed crust, lightly toasted nuts, and a patient chill — with bright, nostalgic flavor. Make a batch, share it, and keep a couple squares for yourself to enjoy with a quiet cup of coffee.