I googled for single servings of peanut butter and found this british web shop:

http://www.sachetsandmore.com/product.php?ProductID=1181

So I made an order and now just wait and see.

Ordering within Europe there is no tax to be paid as it would be if ordering from USA.
Besides some food products are even prohibited for ordering to Europe.
Since I donīt know all the restrictions itīs safer if items are available on this side on the Big Pond.