Open the tub without fully removing the foil.
Press 6 Biscoff cookies into the yogurt in a row, pushing each down until only the very tip is visible.
For two full layers: remove half the yogurt first, press 6 cookies into the base layer, spoon the yogurt back over, then press another 6 cookies into the top.
Cover well and refrigerate overnight (at least 8 hours, minimum 4). Scoop and enjoy.