If you can't find frozen small whole onions, you can use fresh pearl onions. Start by cutting off the root end, but don't cut too much, just nip it off. The root end is the flat end just like any other onion. Put them in boiling water and let them boil for about 1 to 2 minutes. Immediately plunge them into an ice bath. Then, gentle squeeze the pointed end (opposite side of the root end) and the skin is going to come right off.