01 - Preheat oven to 400°F. Line a rimmed baking sheet with parchment paper.
02 - On a lightly floured work surface, unfold the thawed puff pastry sheet. Using a 3-inch heart-shaped cookie cutter, cut out 16 heart shapes. Arrange 8 solid hearts on the prepared baking sheet, spacing them evenly apart.
03 - Using the remaining 8 hearts, cut out centers with a 2-inch heart-shaped cutter to create heart-shaped frames. Reserve centers for another use if desired.
04 - Lightly brush the edges of the 8 solid hearts on the baking sheet with beaten egg. Carefully place the heart frames on top, pressing gently to seal the edges together.
05 - In a small mixing bowl, combine softened cream cheese, granulated sugar, and vanilla extract. Beat with a fork or small whisk until completely smooth and creamy, about 1 minute.
06 - Spoon approximately 1 tablespoon of cream cheese filling into the center cavity of each heart frame. Top each with 1/2 tablespoon strawberry preserves, then arrange 2 to 3 thin strawberry slices on top.
07 - Brush the exposed pastry edges with additional beaten egg for golden coloration.
08 - Bake for 16 to 18 minutes until pastries are deeply golden, puffed, and crisp. Cool on the baking sheet for 10 minutes to allow filling to set.
09 - While pastries cool, whisk powdered sugar, 1 tablespoon milk, and vanilla extract in a small bowl until smooth. Add additional milk 1/4 teaspoon at a time if needed to achieve drizzling consistency.
10 - Drizzle glaze over the cooled danishes in a decorative pattern. Serve warm or at room temperature.