Step 1

Preheat oven to 355°F (180°C). Brush or wipe the inside of an 8” square baking pan with a thin layer of oil. Line with parchment paper: Cut a square of parchment paper a few inches larger than the baking pan. Place the parchment paper on a counter and put the baking pan on top in the middle. Cut one straight slit on each side of the parchment that will meet the corner of the baking pan. Place the sheet inside the baking pan, tucking the flaps in (see photo for reference).

Step 2

In a large glass bowl or stand mixer, combine sugar and grated lemon zest. Rub together with your fingers until fragrant and moistened.

Step 3

Add softened butter into the lemon sugar and beat with an electric mixer until smooth, creamy, and lightened in color. Scrape down the bowl so that it mixes consistently. Add vanilla and salt, beat to combine.

Step 4

Sift flour into the butter mixture, and fold just until no more dry streaks of flour remain.

Step 5

Transfer dough into parchment lined baking pan and spread it out in an even layer. Push a thin layer of dough up the sides to create a border or crust. This will help hold the filling in later on. Bake in the preheated oven for 20-25 minutes - until the edges are lightly golden brown and the top isn’t shiny anymore. Work on the filling while it bakes.

Step 6

Rub the sugar and grated lemon zest with your fingers in a large non-metal bowl until fragrant and yellow. Don’t use a metal bowl to prevent a metallic flavor. Add flour and stir with a whisk to remove any lumps of flour.

Step 7

Add eggs and salt into the lemon sugar mix and whisk very gently by hand - just until the eggs are smooth. Don’t overmix or you’ll get too many air bubbles.

Step 8

Mash the defrosted raspberries and strain the seeds out by pushing the berries through a sieve. Do this into a separate bowl to make sure you have a ¼ cup of raspberry puree. If you have slightly less, add a bit of water to bring it up to ¼ cup. Add lemon juice and raspberry puree into the filling and whisk gently to stir.

Step 9

As soon as the crust bakes, remove from the oven. Do not adjust the parchment paper, you don’t want the crust to detach from the sides of the paper and leave a gap. Immediately pour the filling on top of the crust. Remove large bubbles by poking with a toothpick or using a kitchen torch to gently heat the top.

Step 10

Bake for about 17-20 minutes. It’ll be ready when the filling is completely set on the edges and slightly set in the middle. If you shake the pan vigorously, the middle will have a slight wiggle - it should NOT be liquid. Let it cool in the pan at room temperature for two hours, and then for one hour in the fridge. It will set as it cools. Remove from the pan by lifting up by the paper.

Step 11

Use a sieve to sprinkle powdered sugar on top and cut into bars. Sprinkle powdered sugar on top right before serving so that it doesn’t have time to dissolve. Serve chilled or at room temperature.