Decadent Dessert Bar Recipe

Prepare pan and oven

Preheat the oven to 350°F (175°C). Line an 8x8-inch square baking pan with parchment paper leaving an overhang on two sides for easy removal; lightly grease the parchment.

Whisk together the flour, cocoa powder, granulated sugar, and salt in a medium bowl until evenly combined.

Add the cold diced butter and vanilla extract to the dry mixture. Using a pastry cutter or fingertips, cut the butter into the flour until the mixture resembles coarse crumbs with some pea-sized pieces. Do not overwork—the butter should still be cold.

Press the mixture evenly into the prepared pan, using the bottom of a measuring cup to compact it into a uniform layer about 1/3-inch thick.

Bake the shortbread for 18–22 minutes, until the edges are set and the center looks matte; it will firm more as it cools. Remove from oven and set pan on a wire rack to cool slightly while you prepare the caramel (about 10 minutes). Keep oven on if you plan to toast nuts quickly.

In a medium heavy-bottomed saucepan, heat 1 cup granulated sugar over medium heat. Stir constantly at first with a silicone spatula or whisk until sugar dissolves into a syrup, then leave it undisturbed or stir very gently as it turns amber. Watch carefully to avoid burning.

When the sugar reaches a deep amber color (approximately 8–10 minutes), immediately reduce heat to low and add the butter (0.5 cup) in pieces. Be careful—the mixture will bubble vigorously. Stir until butter is melted and incorporated.

Slowly pour in the 0.5 cup heavy cream while stirring; the caramel will bubble up again. Stir until smooth. If using, add 1 tbsp corn syrup now and stir to combine.

Continue to simmer the caramel on low for 1–2 minutes to slightly thicken; then remove from heat and stir in 1/4 tsp fine sea salt. Let the caramel cool for 5 minutes so it’s slightly thickened but still pourable.

Pour the warm caramel evenly over the slightly cooled shortbread base, tilting the pan if needed to cover the surface. Use an offset spatula to smooth to the edges. Allow the caramel to cool and set at room temperature for about 30–45 minutes, or refrigerate 15–20 minutes to speed up setting. Caramel should be firm but slightly tacky.

Place the 10 oz chocolate chips in a heatproof bowl. In a small saucepan, heat 1/2 cup heavy cream over medium until it just begins to simmer (small bubbles around the edges). Remove from heat and pour over the chocolate. Let sit 1 minute to soften the chocolate.

Stir the chocolate and cream gently until smooth and glossy. Stir in 1 tablespoon of butter for extra shine and spreadability. If ganache seems too thick, warm it briefly over a double boiler or microwave in 10-second bursts, stirring between, until pourable.

Pour the ganache over the set caramel layer and spread quickly and evenly with an offset spatula to create a smooth top. Work efficiently so the ganache levels before beginning to set.

Immediately scatter the toasted chopped nuts, toffee bits, and mini marshmallows (if using) over the ganache. Press them lightly so they adhere. Sprinkle flaky sea salt evenly over the top for contrast.

Allow the dessert bar to sit at room temperature until ganache is set (about 30–45 minutes) or chill in the refrigerator for 20–30 minutes for a firmer slice. If chilled, let sit 10 minutes at room temperature before cutting for cleaner slices.

Using the parchment overhang, lift the whole slab from the pan to a cutting board. Trim edges if desired, then cut into 16 bars (4x4 grid) or 12 larger bars (3x4 grid) with a sharp knife warmed under hot water and wiped dry between cuts to get clean edges.

Store the bars in an airtight container at room temperature for up to 3 days or refrigerated for up to 7 days. If refrigerated, bring to room temperature 15–30 minutes before serving for best texture.