01 -
Throw your raspberries into a blender and pulse until smooth. If you want, push through a metal strainer to get rid of seeds. Simmer the strained mixture in a pot over low-medium heat until it's thick and shrinks down to about 1/4–1/3 cup, usually takes 15-20 minutes. Let it cool all the way.
02 -
Set your oven to 325°F (160°C) and put parchment paper in a 9x13 inch (23x33 cm) baking dish, making sure it hangs over the edges. Combine flour, sugar, corn flour, and salt in a bowl. Pour in the melted butter and stir until you've got a thick mixture. Push it into your lined pan, making small edges around the sides. Bake for 20-25 minutes until it's just starting to turn golden on top. Take it out and gently poke the top with a fork, but don't go all the way through.
03 -
In a big bowl, mix sugar and corn flour together to break up any clumps. Add in your eggs and whisk everything until it's smooth. Stir in your cooled raspberry puree and lemon juice. Don't worry that it's runny. Pour this mix over your baked shortbread.
04 -
Stick them back in the oven at 325°F (160°C) for about 20-25 minutes, or until the top doesn't jiggle anymore. Let them cool in the pan for at least an hour at room temperature, then pop them in the fridge for at least 2 hours.
05 -
Grab the parchment paper edges to pull the whole thing out of the pan. Cut into squares with a sharp knife, wiping it clean between slices. Keep them in a sealed container in your fridge for up to 5 days.