Copypasta'd from a messageboard or something somewhere.

This is what I have thus far.

Ingredients:

 * 300g Flour
 * 200g Butter
 * 100g Sugar
 * 30g Egg Yolk (about two eggs worth)
 * a bit Salt

Directions

1. In advance, sift the flour 2 to 3 times in a strainer.

2. Take the butter out of the fridge and let it thaw to room temperature.
   Knead well with a spoon until it becomes a smooth cream.

3. Add sifted sugar and salt to the butter, and mix until it becomes whitish.

4. Now add the egg yolks, well-beaten. Pour them in bit by bit and mix them in
   evenly.

5. Put the flour in a bowl, and create a big depression in the surface. Pour
   into that all of the butter cream that was made in steps 2, 3, and 4. While
   mixing the butter cream in the centre, take in some of the flour bit by bit and
   mix well. When it has become reasonably hard, form it all into one giant lump.

6. Divide it into parts and roll with hands into even cylinders, about 3cm in
   diameter. Finally, take the cylinders of batter, wrap each of them up, and
   store them in the refrigerator.

7. As necessary, cut the refrigerated batter into slices roughly 5mm thick and
   cook in an oven at 160 degrees Celsius for about 10 minutes. Now you have
   delicious cookies!

I tried the recipe, it was pretty easy. From weighing the ingredients I got:

 * 4 dl flour
 * 1 dl sugar
 * 3 egg yolks

Plus 200 grams butter and "a bit" salt like in the recipe. The eggs I got were
pretty small so I had to use three yolks to get to 30 grams.

The cookies taste pretty good though I think they would be tastier with more
sugar. Also, they took a fair bit longer than 10 minutes to bake. They took on
a light brownish color after 25 minutes at 175 degrees C and turned out to be
nice and crisp at that time.

You're kind of overcooking them then. They're supposed to be the soft and chewy
kind. I baked mine for about 11 minutes. =3

I added just a bit more butter and sugar than asked for in the recipe.. ^^";

A fun thing to try is mixing red food colour with a bit of sugar and making a
tiny thumbprint in the middle of the cookies then fill it with the sugar. Crush
up a red flavoured candy of some kind (I used cherry Campino candies) and put a
couple of the chunks on each cookie. It tastes even better this way.

These kind of cookies, if you spread flour on the counter you can roll them out
and use a cookie cutter. Heart shapes are definitely cute if baking for a loved
one. ^^