01 - Preheat the oven to 150°C. Line a baking sheet with parchment paper and draw a 25x38 cm rectangle on it.
02 - In a clean, dry bowl, beat the egg whites until soft peaks form. Gradually add the granulated sugar, continuing to beat until stiff peaks form.
03 - Gently fold in the white vinegar, cornstarch, poppy seeds, and remaining sugar until just combined.
04 - Spread the meringue mixture onto the prepared parchment along the drawn rectangle, smoothing the surface.
05 - Bake for 15 minutes at 150°C, lower the oven temperature to 120°C, and bake for an additional 45 minutes. Turn off the oven and let the meringue cool completely with the door slightly ajar.
06 - In a medium bowl, whisk together the heavy cream, mascarpone cheese, powdered sugar, lemon zest, and lemon juice until smooth.
07 - Carefully peel the cooled meringue from the parchment and place it on a clean surface. Spread the lemon mascarpone mixture evenly over the meringue, leaving a small border.
08 - Arrange the sliced strawberries over the mascarpone layer.
09 - Starting from one end, gently roll the meringue into a log shape, using the parchment to assist. Transfer the roll to a serving platter.
10 - Slice and serve the pavlova roll, garnished with additional strawberries if desired.