Thaw puff pastry at room temperature for about 30 - 45 minutes. Preheat oven to 400 F (204 C) and line two baking sheets with parchment paper.

In a mixing bowl, combine sliced strawberries, sugar, and cornstarch. Mix well and let sit for 15 minutes.

In another bowl, mix room temperature cream cheese until smooth. Add powdered sugar and vanilla extract, mixing until well combined. Adjust flavor if necessary.

Unfold puff pastry sheet and cut along the folds to create six smaller rectangles. Score a border about ¼ inch from the edges.

Spread 1 tablespoon of cream cheese filling in the center of each rectangle and layer with fresh strawberries. Brush edges with beaten egg and sprinkle with sugar, if desired.

Chill in the fridge for 15 - 20 minutes before baking, to allow the pastry to puff up beautifully. Bake for 20 - 25 minutes until golden brown.

Cool on the baking sheet for 5 minutes before transferring to a cooling rack. Top with optional strawberry jam or a vanilla glaze made from powdered sugar, milk, and vanilla extract.