Set the oven rack as close to the broiler as possible, and preheat the broiler to high. Then place the creme brulees on a sheet pan, and set them underneath the broiler for a minute or two, watching very closely, until the top has browned. Note that this method is not as good as using a torch, since often times oven broilers are not strong enough to quickly brown the top without melting the custard underneath too. If the custard melts, refrigerate the creme brulee for an hour to chill the filling again.