Place all-purpose flour, powdered sugar and salt into a large mixing bowl. Combine the dry ingredients.
Make a well in the center and add in the lemon extract, egg yolk and butter.
Crumble the wet ingredients into the dry ingredients so that your ingredients start to get combined.
Continue to combine and create a smooth dough.
Wrap into cling film and keep to cool in the fridge. Keep at least 30 minutes to cool so that the dough gets hard.
Take out the dough from a cling film and cut into same-sized chunks. Don't make them too large.
Preheat oven to 350° Fahrenheit/ 180° Celsius.
Roll each chunk of dough into a ball and place on a parchment-lined baking tray. Keep some distance between each ball.
Create a crater with your thumb by pressing into each cookie dough.
Fill the cookies with raspberry jelly or jam.
Bake at 350° Fahrenheit/ 180° Celsius.
Allow your cookies to cool and store them afterward in a parchment-lined tin box.
Video
Notes
I removed cups measurements because some couldn't handle it and didn't get the measurements right (not everybody though). So, I recommend you weigh out your ingredients all the time when you want to bake anything. It's important to be exact when you are baking, it's an exact science.