1. Preheat oven to 350
2. Place phyllo shells on a sheet pan and bake until lightly crisp, about 5 minutes
3. Meanwhile, in a small saucepan over high heat, heat milk and butter, stirring occasionally, until milk boils and butter melts.
4. Reduce heat to low, stir in chocolate and vanilla extract until combined.
5. Let chocolate mixture cool slightly, about 2 to 3 minutes; evenly divide among cooked phyllo shells.
6. Sprinkle tarts with sea salt; chill until filling sets, about 10 minutes. Top each tart with 1 tsp whipped cream before serving. Yields 1 tartlet per serving.