Cut two 8x16-inch pieces of parchment. Put the strips in an 8x8 baking pan (preferably straight-sided) so that they cross each other and the excess hangs over the pan's sides. Push the parchment into the bottom and corners of the pan.

Position a rack in the center of the oven and heat the oven to 325 degrees F.

Break the graham crackers into a food processor and process until finely ground. Add the melted butter and pulse until the mixture resembles damp sand. Transfer the crumbs to the lined pan and press them firmly and evenly into the pan. Set aside.

Rinse, dry, and reassemble the food processor. In the cleaned bowl, combine the cream cheese, sugar, lemon juice, and lemon zest. Process until smooth, about 30 seconds, stopping halfway to scrape the sides of the bowl. Add the eggs and process until the mixture is perfectly smooth and blended, stopping to scrape the sides of the bowl as necessary, about another 20 seconds.

Pour the cheesecake mixture into the prepared pan. Bake until the sides are slightly puffed and the center is dry to the touch, about 40 minutes. While the cheesecake is baking, make the Lemon Curd for topping the squares.

When the cheesecake comes out of the oven, pour all of the curd onto the cheesecake and use an offset spatula to spread it evenly. Let cool to room temperature and refrigerate for at least 5 hours, preferably overnight. You can refrigerate it uncovered, as no detectable skin forms on the curd.

When the cheesecake is thoroughly chilled, carefully lift it out of the pan using the parchment "handles" and onto a cutting board. Slide the parchment out and discard it. Using a large, sharp knife, cut the cheesecake into quarters, and then cut each quarter into four equal squares. To make clean cuts, wipe the knife blade with a damp paper towel between each slice.

For the best results, measure your flour by weight instead of volume. (1 cup of all-purpose flour equals 4-1/2 ounces) If you don't have a scale, be sure to use the proper technique when filling your measuring cups.

These cheesecake squares are a perfect addition to a picnic menu. To make packing and serving them easier, flatten a paper muffin liner, set a cheesecake square in the center, and fold the sides up. Repeat for the remaining squares, and then pack them in a box or plastic container. The squares need to be kept cool, so remember to include freezer packs in your picnic basket.

Set a fine strainer over a medium bowl. In another medium bowl, whisk the lemon juice, sugar, and eggs until thoroughly combined and most of the sugar has dissolved.

Pour the lemon mixture into a small, nonreactive saucepan. Cook over medium heat, stirring frequently with a wooden spoon or heatproof spatula, until the curd is steaming (but not boiling) and thickened and registers about 175 degrees F on an instant-read thermometer, 3 to 7 minutes.

Take the curd off the heat, add the butter, and stir until the butter has melted. Pour the curd through the strainer to get rid of any lumps. Set aside but use to top the cheesecake while still warm.