Put the butter, sugar and syrup in a bowl and mix with a mixer until everything is creamy (about 3 minutes).
Add the egg and mix until it is incorporated.
Stir in the gingerbread spice and salt.
Sift the flour to the batter and mix on the lowest speed through the dough (until just incorporated).
Divide the dough in half, make from each dough a flat disk and wrap in plastic wrap.
Put that in the refrigerator for at least 1 hour.
Place one of the two pieces of dough on the baking mat and cover with plastic foil.
Roll with a rolling pin until you have a dough of approximately 0.5 cm thickness.
With a cookie cutter, stick out the cookies. Place on the baking mat on a baking tray and put in the refrigerator (at least half an hour).
Grab the second disc of dough, roll out under plastic foil and again cut out the biscuits. But with these batch of cookies, you grab a smaller cookie cutter and cut out a nice form in the middle of a cookie (in my case a heart).
Also cool these cookies in the refrigerator on a baking tray
Preheat oven to 180 degrees Celsius.
Remove the cookies from the refrigerator and cook in about 12 minutes until golden brown.
Let them cool to room temperature.
Pick up a whole cookie, spread some jelly on it and top with a second cookie from the other baking sheet (with the cut out in the middle) right on top.