Preheat oven to 375°F (190°C). Line a baking sheet with parchment paper.

Make optional fresh strawberry compote: In a small saucepan combine diced strawberries, 1 tablespoon sugar, and lemon juice. Cook over medium heat 3–4 minutes until juicy. Stir cornstarch with 1 tablespoon water, add to the pan, and cook 1 minute until glossy and thick. Cool completely.

Make cream cheese filling: Beat softened cream cheese with 1/4 cup powdered sugar, vanilla, and optional lemon zest until smooth and spreadable.

Prepare pastry: Unfold puff pastry on a lightly floured surface. Roll gently to even thickness. Cut 8 heart shapes. Lightly score a smaller heart inside each, leaving a 1/3-inch border without cutting through.

Egg wash: Whisk egg with 1 tablespoon milk. Brush the borders lightly and sprinkle edges with 1 tablespoon granulated sugar.

Fill: Spoon 1–2 teaspoons cream cheese filling into the center of each heart, staying inside the scored line. Top with 1 teaspoon strawberry preserves or cooled compote. Add a few thin strawberry slices if using.

Bake: Transfer hearts to the prepared sheet and bake 15–18 minutes, until puffed and deep golden at the edges and the centers are set.

Finish: Cool 5 minutes. Dust with powdered sugar and, if desired, drizzle with melted white chocolate. Garnish with tiny mint leaves. Serve warm.

Storage: Refrigerate leftovers up to 3 days. Reheat at 325°F (165°C) for 5–7 minutes or in the air fryer 3 minutes at 320°F. Freeze unbaked hearts on a tray until firm, then bag and bake from frozen, adding 2–3 minutes.