Preheat the oven to 350 degrees F and line an 8x8 inch pan with parchment paper.
Melt the butter in a microwave safe bowl, then stir in the sugar until smooth.
Add the eggs and vanilla extract, and mix until fully combined.
Stir in the black cocoa powder, flour, and salt until no dry streaks remain.
Spread the batter evenly in the prepared pan and bake for 22 minutes.
Let the brownies cool completely in the pan.
Melt the white chocolate chips in a small bowl until smooth, then transfer to a piping bag or zip top bag with one corner snipped.
Pipe the melted white chocolate in four concentric circles on top of the cooled brownies, then drag a toothpick from the center outward to form a web pattern on each section.