Prepare the Lemon Filling: In a medium bowl, combine the softened cream cheese, powdered sugar, lemon zest, lemon juice, and 2 tablespoons of poppy seeds. Beat with an electric mixer until smooth and creamy.

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

Roll Out the Pastry: Unfold one sheet of puff pastry on a lightly floured surface. Gently roll it out into a roughly 12x16 inch rectangle.

Cut into Triangles: Using a sharp knife or a pizza cutter, cut the pastry into 6-8 equal triangles.

Add the Filling: Spoon a generous tablespoon of the lemon filling onto the wide end of each triangle.

Roll 'Em Up: Starting at the wide end, gently roll up each triangle towards the point. Place them on the prepared baking sheet, point-side down, curving the ends slightly to form a crescent shape.

Egg Wash: In a small bowl, whisk together the egg and water. Brush the tops of the croissants with the egg wash.

Sprinkle: Sprinkle the croissants with extra poppy seeds and coarse sugar (if using).

Bake: Bake for 18-20 minutes, or until golden brown and puffed up.

Cool Slightly: Let the croissants cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.