Best Double Chocolate Brownies

These brownies earn the “double chocolate” name with two forms of chocolate: melted unsweetened squares for deep, intense cocoa flavor, plus chocolate chips that hold their shape during baking and create gooey pockets throughout the bars.

Mini marshmallows folded into the batter are the textural surprise. They melt during baking, leaving fluffy, slightly chewy pockets that play beautifully against the dense brownie crumb. Don’t substitute large marshmallows; they leave gaping holes.

Melting the chocolate and butter together gently is critical. Chocolate seizes if it gets too hot or comes into contact with even a drop of water. Use a double boiler or melt in 30-second microwave bursts, stirring between each. Cool the melted chocolate before adding it to the eggs to prevent scrambling.

The “do not overcook” warning is genuine. The brownies look slightly underdone when properly baked, but they firm up significantly as they cool. Overbaked brownies turn dry and cakey, losing their signature fudge texture.

Let the brownies cool completely in the pan before slicing. Hot brownies tear and crumble. A wire rack and 30 minutes of patience yield clean, sharp squares.

Serve plain with cold milk, or take them over the top with a scoop of vanilla ice cream and a drizzle of warm chocolate sauce.

Pro Tips

• Toast the walnuts for 8 minutes at 350°F (175°C) before chopping for richer flavor.
• Line the pan with parchment paper with a sling overhanging the sides for clean removal.
• Refrigerate before slicing for the cleanest, sharpest cuts.
• Store airtight at room temperature for 3 days, or freeze 3 months.

Variations

• Substitute pecans or hazelnuts for the walnuts.
• Use peanut butter chips alongside chocolate chips for a chocolate-peanut twist.
• Drizzle with caramel sauce and flaky sea salt for salted-caramel brownies.