Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper. Yes, preheating matters—no one wants soggy bites.
Beat the cream cheese until creamy. Stir in lemon juice and vanilla. You want a smooth, dreamy filling, not a dairy hedge fund.
Make the peach filling: combine peaches, sugar, and cornstarch in a small saucepan. Cook over medium heat until it thickens and looks glossy. About 4-6 minutes. Let cool slightly.
Roll out the puff pastry on a lightly floured surface. Cut into 12 equal squares or use a round cutter for variety. Fight the urge to overwork the dough—keep it light and flaky.
Place a teaspoon of cream cheese filling in the center of each square. Add a small spoonful of peach filling on top, then fold corners to meet in the center to form a little package (or just fold into triangles if you prefer).
Seal edges with a fork and brush with beaten egg for that glossy, golden finish. Sprinkle with a pinch of sugar if you’re feeling extra fancy.
Bake for 12-15 minutes, or until puffed and golden. Keep an eye on them—people will try to steal them from the cooling rack.
Cool briefly before serving. Dust with powdered sugar if you like a little drama on the plate.