If you don’t have a blowtorch, place right under a broiler on the top rack for 1-3 minutes with the oven door open. You want the sugar to caramelize, but you don’t want the eggs to cook. I've never tried this method but I've read it's not as easy as it sounds... hope this will work for you.
With the kitchen blowtorch, each one has varying degree of heat so make sure it's at least 1½ to 2 inches from creme when you start melting the sugar.
Adapted from Food Network