How to Make It
Preheat oven to 400°F. Place puff pastry sheets on a lightly floured surface, and cut each sheet into 9 (3-inch) squares. Place squares in a single layer on a parchment paper-lined baking sheet. Whisk together egg yolk and 1 tablespoon of the cream. Brush mixture evenly over pastry squares, and sprinkle squares evenly with 2 tablespoons of the granulated sugar. Bake until lightly browned and puffed, 12 to 15 minutes. Cool 10 minutes.
While pastry squares bake, combine strawberries, lemon juice, and remaining 2 tablespoons granulated sugar. Let stand until ready to use.
Beat powdered sugar, vanilla, and remaining cream with a heavy-duty electric stand mixer fitted with the whisk attachment on high speed until soft peaks form, 2 to 3 minutes.
Place chopped white chocolate in a microwave-safe bowl; microwave on HIGH until smooth and melted, about 30 seconds, stirring every 10 seconds.
Place 1 pastry square on each of 9 plates. Top each with a generous dollop of whipped cream, 1/2 cup of the strawberry mixture (including accumulated juices), a second pastry square, a second dollop of whipped cream, and 1/2 cup of the strawberry mixture. Drizzle each serving with melted white chocolate, and garnish with a mint sprig.