Preheat your oven to 350°F (175°C) and prepare a 9x9-inch baking pan.

In a medium saucepan, combine the unsalted butter, granulated sugar, and unsweetened cocoa powder. Heat on low until smooth and melted, about 5 minutes.

Whisk in large eggs one at a time until fully incorporated, about 2-3 minutes.

Sift together all-purpose flour and a pinch of salt in a separate bowl, then fold this into the chocolate batter.

Pour the brownie batter into the prepared pan and bake for 25-30 minutes, checking for doneness with a toothpick.

Once baked, cool brownies in the pan for about 30 minutes on a wire rack.

Melt the white chocolate chips in a microwave-safe bowl in 30-second increments, stirring until smooth. Mix in black gel food coloring if using.

Drizzle the melted white chocolate over the brownies in a circular pattern, creating a spider web design.

Allow the decoration to set for 15-20 minutes, then cut into squares and serve.