Preheat oven to 400°F (200°C). Unfold the puff pastry sheets on a flat surface. Using a knife, cut along the fold lines to create three equal strips per sheet. Then cut each strip in half, making a total of 12 rectangles.

Arrange the pastry rectangles on a large, ungreased baking sheet, leaving about 1 inch of space between them.

Step 2: Score and Poke the Pastry

Use a paring knife to lightly score a ¾-inch border around each rectangle. Then, use a fork to poke holes in the center of each piece to prevent excessive rising.

Step 3: Make the Cream Cheese Filling

In a small bowl, mix together cream cheese, 2 tablespoons sugar, and vanilla extract until smooth. Spoon equal amounts into the center of each pastry rectangle and spread within the inside border.

Step 4: Add the Blueberry Topping

In another bowl, toss the blueberries with lemon juice and 1 tablespoon sugar. Evenly distribute them over the cream cheese filling.

Step 5: Apply the Egg Wash

In a small bowl, whisk together egg and water. Use a pastry brush to lightly coat the outer border of each pastry with the egg wash for a golden finish.

Step 6: Bake to Perfection

Bake at 400°F for 18 minutes or until golden brown and puffed up. Remove from the oven and cool for 10 minutes on a wire rack.

Step 7: Make the Icing & Drizzle

In a bowl, whisk together powdered sugar and heavy cream until smooth. Drizzle over the cooled pastries for a delicious finishing touch.