Press the four hard-boiled egg yolks through a sieve and set aside.
Put the first four ingredients into food processor.
Cut cold butter into pieces and add to the flour mixture. Mix in food processor until pea sized clumps are formed.
Add hard-boiled and raw egg yolks and mix until large clumps are formed. Don't overmix dough. Take dough out of food processor and knead a few times to form the dough. Wrap dough in foil and put in the fridge for at least 15 minutes.
Take dough out of the fridge and divide into portions you can handle. Knead the dough a few times.
Flour the workspace and the dough very lightly and roll out thin (like a back of a knife) using a rolling pin.
Cut out cookies using cookies forms. To make the terrace cookies you need a "large", a "medium" and a "small" cookie form of the same shape. If you don't have cookie forms in different sizes, you can cut out cookies with a knife.
Bake cookies for 7-10 minutes. Baking time depends on your oven. Cookies should be lightly brown (don't overbake them).
Let cool cookies completey on a cooling rack.
Meanwhile heat up the jam on low heat so that it gets a little more fluid.
Make the terrace cookies: put a little of the jam on the underside of the medium sized cookie and put on the large one. Put a little jam on the small cookie and put on the medium one. Dust with caster sugar.
Store cookies in an airtight cookie box.
NOTE: The number of cookies depends on the size of your cookie forms and how thin you roll out the dough. So my number is just a vague guess.
NOTE: Baking/cooking time is given for one baking tray.