Preheat oven to 350 F. Lightly butter then line an 8x8" square pan with parchment paper. Leave some excess parchment paper hanging over at least two sides to make it easier to remove the bars once baked and cooled.

Place the graham crackers into a food processor fitted with the metal blade. Pulse graham crackers into fine crumbs. If you don't have a food processor, you can place graham crackers in a large zip lock bag and crush them with a rolling pin. Make sure to break up any large pieces so that you're left with only fine crumbs.

In a medium sized mixing bowl, stir together the graham cracker crumbs, sugar and salt. Stir in the melted butter til thick, sandy and well combined.

Pour the mixture into the prepared 8 inch pan. Use your hands or the bottom of a ¼ measuring cup to press the mixture into the bottom and slightly (about 1 inch) up the sides of the prepared pan. Press with medium pressure but do not press down too hard. Press til the mixture is compact.

Bake for 10 minutes, until set. Remove from oven and allow to cool while you prepare the lemon cheesecake filling. Reduce oven to 325 F.

In a medium sized mixing bowl or the bowl of an electric mixer fitted with the paddle attachment, beat the lemon zest and sugar briefly til zest is incorporated into the sugar. Add the cream cheese, flour, and salt and beat on medium speed for 1 minute, til smooth.

Turn the mixer to low speed and mix in the eggs one at a time, followed by the sour cream, vanilla, and lemon juice and beat until just combined, about 1 minute. Do not overmix.

Pour the batter over the cooled or slightly cooled graham cracker crust. Bake at 325 F for 38-43 minutes, until the filling is set but still a little bit jiggly in the middle. Avoid overbaking since the cheesecake will continue cooking while it cools.

Set pan on a wire rack to cool at room temperature for 45 minutes then place in the fridge to cool for at least 4 hours or overnight. Make the rapsberry curd while the cheesecake bars cool.

Use the parchment paper to lift the bars out of the pan. Spread as much curd over the cheesecake bars. Slice with a long, sharp knife. Alternatively, instead of spreading curd on bars, you can spoon the raspberry curd over individual cheesecake bars. Enjoy!

In a medium sized heavy bottom non-reactive saucepan such as stainless steel or copper, combine the sugar and lemon zest. Rub the zest into the sugar with your fingertips. Rubbing the zest into the sugar is optional. It will help release the oils of the zest and enhance the lemon flavor.

Add the egg, egg yolk, and salt to the saucepan and whisk with a silicone whisk til smooth.

Stir in the raspberries and lemon juice. Stir constantly with a rubber spatula or silicone whisk over medium-low heat til mixture comes to a simmer then thickens enough to coat the back of a spoon, should take around 10 minutes.

Set a large fine mesh sieve over a large non-metal bowl. Strain the curd through the sieve, pushing it through the sieve with a spatula to remove the seeds. Discard the seeds.

Stir in the cold, chopped butter til melted. Gently press a piece of plastic wrap directly on the surface of the curd. Set the bowl in the refrigerator to cool and thicken for at least 2 hours.