yorkshire pudding

when i make yorkshire and take it out of the oven it colapses. i use the ingrediants at room temp. i heat the muffin tin with some dripings in it in the oven befor i put the ingrediants into them. what might i be doing wrong

They will fall flat if they are removed from the oven too soon. If they do not get slightly crispy on the outside the structure of the egg and flour mixture does not fully amalgamate meaning its structure will not hold its own weight . . . think of building a sky scraper out of wood, eventually it will buckle and collapse under its own weight.