1. Preparing the Oven and Muffin Tin

Preheat the oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners. This prevents sticking and makes removing the cupcakes easier after baking.

2. Melting the Chocolate and Butter

In a microwave-safe bowl, combine the chopped semisweet chocolate and butter. Microwave in 30-second intervals, stirring after each interval, until the mixture is smooth. This should take about one to two minutes in total. If using a stovetop, melt the chocolate and butter in a heatproof bowl over a pot of simmering water, stirring constantly.

3. Mixing the Batter

Once the chocolate and butter are fully melted and smooth, mix in the granulated sugar. Stir until well combined. Add the eggs one at a time, mixing thoroughly after each addition. This ensures a smooth texture and helps incorporate air into the batter. Stir in the vanilla extract for added flavor.

Gently fold in the flour and salt. Be careful not to overmix, as this can make the cupcakes dense. Stir just until the ingredients are combined and no streaks of flour remain.

4. Preparing the Raspberry Filling

In a small saucepan, heat the raspberry preserves over low heat until they become liquefied. Remove from heat and immediately stir in the chopped chocolate. Mix until the chocolate melts and the mixture becomes smooth. Stir in the heavy cream until fully incorporated. The filling should have a velvety consistency.

5. Assembling the Cupcakes

Divide the chocolate batter evenly among the prepared muffin cups, filling each about halfway. Spoon the raspberry filling evenly over the cupcake batter in each cup. This will create the signature lava effect when baked.

6. Baking the Cupcakes

Bake for 12 to 14 minutes, or until the edges are set but the centers remain slightly soft. Avoid overbaking, as the goal is to keep the centers molten. The tops should appear slightly domed but not dry.

7. Cooling and Serving

Allow the cupcakes to cool in the pan for five minutes before transferring them to a wire rack. Serve warm for the best molten texture. If serving later, reheat slightly before enjoying.