Prepare the Pan: Line an 8x8-inch square pan with parchment paper for easy lifting later.

Melt Chocolate and Milk: In a medium saucepan over low heat, combine chocolate chips and sweetened condensed milk, stirring frequently until smooth and glossy, about 5-7 minutes.

Spread the Chocolate Mixture: Pour the chocolate mixture into the prepared pan and spread evenly. Tap the pan to remove air bubbles.

Warm the Raspberry Jam: Warm raspberry jam in a microwave-safe bowl in short bursts of 15 seconds, stirring in between, until easily drizzled.

Drizzle and Swirl: Drizzle the warmed raspberry jam over the chocolate layer and swirl it gently with a knife or skewer.

Chill to Set: Transfer the pan to the refrigerator and chill for at least 2 hours until firm.

Cut and Serve: Lift the fudge out using the parchment overhang, cut into squares, and serve cold.