Bring lemon juice, water, and sugar to boil over medium heat, stirring occasionally, until the sugar dissolves, about 5 minutes. Remove from heat; stir in sherry. Divide the pound cake evenly between four 2-cup mason jars, then pour the lemon and sugar mixture on top.
Combine the mascarpone cheese, 3/4 cup lemon curd, and lemon zest in a bowl. Divide the cheese mixture among the jars, pressing down with the back of a spoon to create an even layer. Spoon the remaining 1 cup lemon curd over the cheese mixture to create another layer. Top with the raspberries, then sprinkle with chocolate. Cover and refrigerate for at least 15 minutes, or up to 24 hours. Top with whipped cream before serving.