Preheat your oven to 350°F (175°C). Line a 9x13 inch baking pan with parchment paper, leaving an overhang for easy removal.

In a large mixing bowl, whisk together the melted butter, granulated sugar, and brown sugar until smooth. Add the eggs and vanilla and mix until well combined.

Sift in the flour, cocoa powder, and salt. Gently fold into the wet ingredients with a spatula until just combined. Do not overmix.

Spread the brownie batter evenly into the prepared pan.

In a separate bowl, beat the softened cream cheese and 0.25 cup granulated sugar until smooth. Add the egg yolk, 0.5 teaspoon vanilla extract, and a few drops of orange gel food coloring; mix until creamy and evenly colored.

Drop spoonfuls of the orange cheesecake mixture over the brownie batter. Swirl gently with a toothpick or skewer for a marbled effect.

Sprinkle the top with Halloween sprinkles and, if desired, mini chocolate chips or candy eyeballs.

Bake for 33-35 minutes, or until the center is almost set and a toothpick inserted comes out with a few moist crumbs.

Let brownies cool completely in the pan before lifting out and slicing into squares.