In microwave-safe bowl, combine chopped chocolate and 2 tablespoons heavy cream. Microwave for 1 minute, remove and stir. Continue to microwave in 30-second intervals until chocolate has melted, stir and let chocolate cool.
Using stand mixer with whisk attachment, whisk chilled heavy cream in a chilled bowl on high speed until thick and stiff peaks begin to form (about 2-3 minutes). Remove and carefully fold in cooled white chocolate. Return bowl to mixer and whisk for 30 seconds.
Place a large tablespoon of white chocolate mixture in the bottoms of four glasses. Crush 4 shortbread cookies and place crumbs on white chocolate layer. Spoon a generous spoonful of lemon fruit filling into each glass and top with 4 more crushed cookies. Top with remaining white chocolate and garnish each glass with a cookie.