Prepare the Puff Pastry:

• Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.
• Roll out the puff pastry sheet on a lightly floured surface to smooth out any creases. Use a sharp knife to trim the edges of the pastry into a rectangle (about 9×6 inches) or circle, depending on your preference.
• Place the puff pastry on the prepared baking sheet. Use a fork to prick the entire surface of the pastry, leaving a border around the edges. This will help the center of the pastry to stay flat while baking.
• Bake the puff pastry for 15-18 minutes or until golden brown and puffed. Let it cool on the baking sheet.

Make the Lemon Cream Filling:

• In a medium saucepan, whisk together the lemon juice, lemon zest, sugar, and egg yolks.
• In a separate small bowl, whisk the cornstarch with a tablespoon of water to form a slurry. Add this to the lemon mixture and stir to combine.
• Heat the mixture over medium heat, stirring constantly until it thickens to the consistency of pudding (about 5-7 minutes).
• Once thickened, remove from heat and stir in the heavy cream, butter, and a pinch of salt until smooth.
• Let the lemon cream cool for about 10 minutes before transferring it to a small bowl. Cover and refrigerate the cream for at least 1 hour to fully set.

Assemble the Tart:

• Once the puff pastry has cooled and the lemon cream filling has set, spread the lemon cream over the center of the puff pastry, leaving the edges exposed to show the flaky crust.
• Gently arrange the fresh blueberries over the lemon cream, distributing them evenly.
• Optionally, dust with powdered sugar for an extra touch of sweetness and decoration.

Serve and Enjoy:

• Slice the tart into squares or rectangles and serve immediately, or refrigerate until ready to serve.
• This tart is best enjoyed fresh but can be stored in the refrigerator for up to 2 days.