Wash and thoroughly dry all fresh fruit to prevent water from diluting the chocolate fondue. Cut strawberries in half, slice bananas into 1-inch rounds, and cut pineapple into 1-inch chunks. Arrange the prepared fruit on a serving platter alongside shortbread cookies and marshmallows, making it easy for guests to grab and dip. Set aside until ready to serve.

Chop the dark chocolate and milk chocolate into small, uniform pieces to ensure even melting. In a microwave-safe bowl, combine the chopped dark and milk chocolate with heavy cream, unsalted butter, espresso powder, and salt. The espresso powder will deepen the chocolate flavor without making it taste like coffee—I always add it to enhance the richness. Microwave on 50% power for 2 minutes, stirring halfway through to ensure even melting and prevent scorching.

Remove the chocolate mixture from the microwave and stir thoroughly until completely smooth and glossy. Add the vanilla extract and stir to combine. If the fondue seems too thick, add a tablespoon of heavy cream at a time and stir until you reach the desired consistency—it should be pourable but still coat the fruit generously. I prefer mine slightly thick so it clings to the dippers rather than dripping off.

Transfer the warm chocolate fondue to a fondue pot or a small bowl set over a warm water bath to keep it at an ideal dipping temperature. If the fondue thickens while serving, microwave it for 15 seconds at 50% power and stir gently to restore its pourable consistency. Arrange the prepared fruit and dippers around the chocolate and invite guests to dip and enjoy.