Line an 8×8 inch pan with parchment paper, leaving some overhang on the sides.

In a microwave-safe bowl, combine the white chocolate chips and sweetened condensed milk. Microwave in 30-second intervals, stirring well after each, until smooth and fully melted (about 1.5 to 2 minutes total).

Add the vanilla extract and a pinch of salt into the melted chocolate mixture. Stir until smooth.

Pour the mixture into the prepared pan, spreading it out evenly. Smooth the top with a spatula.

Drop small spoonfuls of the warmed raspberry jam evenly over the top of the fudge mixture.

Gently swirl the raspberry jam into the fudge using a butter knife or the tip of a spatula.

Place the pan in the refrigerator and chill for at least 3 hours, or until firm. Lift the fudge from the pan using the parchment paper overhang. Cut into 36 small squares and serve.