Preheat the oven to 350°F (175°C). Grease and line a 9x9 inch baking pan with parchment paper.

In a mixing bowl, whisk together melted butter and sugar until smooth.

Add eggs one at a time, mixing well after each addition, then stir in vanilla extract.

In another bowl, sift together flour, cocoa powder, and salt. Gradually add to the wet ingredients, mixing until just combined.

Pour the brownie batter into the prepared baking pan and spread evenly.

Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted comes out with a few moist crumbs.

Allow brownies to cool completely in the pan.

In a double boiler or microwave-safe bowl, melt the white chocolate chips with vegetable oil until smooth.

Transfer the melted chocolate to a piping bag or a plastic bag with a corner snipped off.

Once the brownies are cool, pipe a spiral starting from the center and working outward to create a web pattern.

Use a toothpick to drag lines from the center to the edges to form the spider web effect.

Let the chocolate set before cutting the brownies into squares.