Line a 9x13 inch pan with parchment paper.
In a 6-quart Dutch oven, over high heat, mix sugar, evaporated milk, butter, and cream cheese together, cooking until the candy thermometer reads 234°F, stirring often. Remove from heat.
Stir in the marshmallow creme and vanilla.
In a large bowl, pour in the white baking chips.
In a second large bowl, pour in the milk chocolate, semi-sweet chocolate chips, and cocoa powder.
Pour half of the sugar mixture into the bowl with white chips and the other half into the bowl with the chocolate chips. Use some elbow grease and stir to get the chips melted in both bowls.
Pour half of the white mixture into the pan, spreading evenly. Add half the chocolate mixture over top. Repeat with the other halves of the white and chocolate mixtures.
Swirl a buttered knife through the layers, creating the marbled design.
Let the fudge cool about 2 hours before cutting.