Preheat your oven to 400 degrees F. Unfold one sheet of puff pastry onto a work surface and cut it into six rectangles. Transfer to a parchment-lined baking sheet, spacing them ½ inch apart. Repeat with the second sheet.

In a small bowl, mix strawberry jam, cornstarch, and lemon juice. Spoon a heaping tablespoon onto each rectangle, leaving a ½-inch border.

In another bowl, whisk the egg with 1 tablespoon of cream. Brush the border of each rectangle with the egg wash.

Prick the reserved pastry rectangles with a fork, place them on top of the filled rectangles, and seal the edges. Crimp the edges with a fork, brush with egg wash, and sprinkle with coarse sugar.

Bake for 18 to 20 minutes until golden brown, rotating the pan halfway. Cool on the pan for 30 minutes.

For the glaze, whisk powdered sugar, vanilla, salt, and remaining cream until smooth. Drizzle over cooled strudels.