Take one part of the dough from the fridge and roll it out on a lightly floured surface until between 1/4-1/6-inch (4-6 mm) thick. Sprinkle the dough with flour as you're rolling it out.
Use Linzer cookies cutter to cut out the cookies - half of the cookies should have a 'window' cut out. You can also use regular cookie cutters in different sizes (and different shapes, it could be circles, hearts, stars, or flowers), cut out the cookies with a large heart-shaped (for example) cookie cutter, then cut smaller hearts into the centers of half of the hearts.
If the dough gets a little bit sticky, sprinkle it well with flour. If it gets more sticky, put it back in the fridge to chill for a bit.
Gather the scraps, knead them again into a ball of dough, re-roll and cut out the cookies until all the dough has been used.
Transfer the cookies to parchment paper-lined baking sheets. You can use an offset spatula to do that or a large sharp knife.