Preheat your oven to 350°F (175°C). Line a 9×13-inch baking pan with parchment paper (leave an overhang on two sides so you can lift the brownies out easily). Lightly grease the parchment/sides.

In a medium saucepan or microwave-safe bowl, melt 1 cup (2 sticks) butter until liquid.

Stir in 2 cups sugar until mostly combined.

Let it cool for a minute, then whisk in 4 large eggs one at a time, then 2 tsp vanilla extract until smooth.

In a separate bowl, sift (or whisk) together 1 cup all-purpose flour, 1 cup unsweetened cocoa powder, ½ tsp baking powder, and ½ tsp salt.

Sifting helps remove lumps in the cocoa.

Fold the dry mix into the wet mixture gently until just combined.

Don’t overmix — you want fudgy brownies. The batter will be thick and glossy.

Pour batter into your prepared pan and smooth the top. Bake 25–30 minutes at 350°F.

Start checking at 22 minutes — a toothpick inserted near the center should come out with a few moist crumbs (not raw batter).

For fudgier brownies, err on the shorter side.

Remove from oven and let the pan cool on a wire rack until completely cool. Cooling fully is important — the white chocolate web will melt if the brownies are warm.

Put ½ cup white chocolate chips (or candy melts) + 1 tsp vegetable oil in a microwave-safe bowl.

Microwave in 20–30 second bursts, stirring between each, until smooth. (Or melt in a double boiler.)

Transfer the melted white chocolate to a small piping bag, squeeze bottle, or a zip-top bag and snip a tiny corner.

Lift the cooled brownie slab from the pan using the parchment. Pipe concentric circles of white chocolate across the surface — start with a small dollop in the center, then circle around it in rings (spacing about 1–1.5 cm).

Use a toothpick or skewer: starting at the center, drag the tip straight outward to the edge to create spokes — repeat every 1–1.5 cm all the way around (about 8–12 spokes). Clean the toothpick if it gets messy.

The concentric rings + outward drags automatically form the spiderweb pattern.

Let the white chocolate set at room temperature or pop the brownies in the fridge for 10–15 minutes to firm the web.

Melt a little dark chocolate, pipe a small teardrop for the body and a smaller dot for the head, then add 6 thin legs with a toothpick.

Place a few spiders on the web for extra creep factor.

Use the parchment overhang to lift the slab out and slice into squares with a sharp knife (wipe the knife between cuts for clean edges).

Store in an airtight container at room temp for up to 3 days, or refrigerate for up to 5 days.

You can freeze cut brownies for up to 2 months — thaw to room temp before serving.