Take the mascarpone out of the refrigerator and allow it to come to room temperature.
Wash and core strawberries and place in a colander to air dry.
Add chocolate to the double boiler.
Add mascarpone to a medium bowl, stir in lemon juice, powdered sugar, and vanilla.
Add mascarpone to a pastry bag fitted with a star tip.
Pipe filling into strawberries and arrange on a platter.
Drizzle melted chocolate onto the strawberries.
Optional: sprinkle chopped walnuts, shredded coconut, or sprinkles onto chocolate before it hardens.