Butter an 8-inch square baking pan and then line it with parchment paper, letting the ends of the parchment paper drape over two opposite sides of the pan. Butter the parchment paper as well.

Whisk the raspberry preserves in a small bowl to loosen it and then transfer it to a zipper sealable plastic bag. Set it aside.

Combine the sugar, evaporated milk, butter, marshmallow cream and salt in a medium saucepan and bring the mixture to a boil. Cook for 5 minutes, stirring regularly.

Remove the pan from the heat and stir in the white chocolate chips. Stir until the chocolate has melted and then stir in the vanilla extract and half of the pistachios.

Pour the mixture into the prepared baking pan and smooth it out using a flat spatula or by banging the pan on the counter. Cut off a small corner of the zip-lock bag with the raspberry preserves. Drizzle thin lines of the raspberry preserves across the fudge and then run a knife or skewer through the lines to swirl the raspberry into the fudge. Sprinkle the fudge with the remaining chopped pistachio nuts, pushing them gently into the fudge with the back of a spatula. Let the fudge cool at room temperature.

When ready to enjoy, cut the fudge into squares and serve. Store in an airtight container.