In a mixing bowl, add the cream cheese, sugar, lemon juice, and egg. Use a mixer to combine all these ingredients until smooth and creamy. Set aside.

In a saucepan over medium heat, add the blueberries, sugar, and lemon juice.

Stir every couple of minutes and let cook until a thick blueberry sauce forms, about 8 minutes. Strain the blueberry sauce from the whole blueberries and keep the sauce and blueberries in separate bowls.

Unfold the puff pastry and using a rolling pin, press out the creases. Using a heart shaped cookie cutter, cut out as many hearts as you can.

Using a paring knife, cut another heart in the center following the exact shape of the cut out about ¾ inch from the edge of the dough. You are creating separation fro the edges of the pastry to rise and the center to stay held down with the filling, so do not cut the center heart fully.

Fill the center of each puff pastry with 2 tablespoons of the cream cheese filling spreading to fully fill the inner heart. Place about 1 tablespoon of the whole blueberries on top of the cream cheese filling.

Place the baking tray in the refrigerator to chill the dough for 30 minutes.

Preaheat the oven to 400°F.

Remove the tray from the refrigerator and brush the edges of the puff pastry hearts with egg wash.

Bake for 12 minutes or until the pastry edges are golden brown.

Remove from the oven and let cool for 5 minutes.

Drizzle with the blueberry sauce and sprinkle with powdered sugar.