Cream butter & sugar in your electric kitchen aid mixer. If using egg yolk, then add that, I didn't use it.
Add your vanilla or almond extract to it
Slowly add your flour to the mix along with salt
With the help of the spatula, mix everything until combined
You will have a soft pliable dough
Place parchment paper on the baking tray. Taking small portion at a time, make smooth dough balls and put them on the tray a couple of inches apart
Using the back of the measuring spoon, make an indent or you can use your thumb.
Cover it with the plastic serene wrap and place it in the fridge for about 45 mins to an hour
At this time, fill the indents with your choice of jam. Don't overfill it
Place it back in the fridge for another 10 mins
Heat the oven at 350F and place the baking sheet in the oven
Cookies should take 12-13 mins depending on the oven. Keep an eye after 11 mins to make sure the bottoms don't burn
Once you take them out of the oven, let it sit for a min and then with the help of the spatula, transfer one by one on the cooling rack.
The cookies will harden a bit once they have completely cooled down.
Place them in an air tight container and enjoy them with a cup of tea or coffee.