I was introduced to Vegemite by a friend in Hong Kong who was from Melbourne. Almost everyone we knew in Hong Kong was actually from somewhere else, which is a wonderful situation. But that's another story. She rang up one day and said she was stopping by with something for us to eat. She arrived with her two little boys and a small plate of soda crackers that had on them butter and Vegemite. Now if you've ever seen Vegemite you'd question the sanity of eating it. But since a friend had gone to all the bother of bringing it over for us to try, we did. Well I've been hooked on the stuff ever since. But in my family there are only three of us who eat - myself, Corey (daughter #3) and Emily (my grand-daughter). Corey and I like to make sure that there is always some in the house, which isn't easy as Americans haven't embraced Vegemite yet.
In my opinion the secret to a great Vegemite snack is butter. It goes great on crackers, but it's at its best on good bread, like artisan bread. If I make French bread for dinner and there's some left over I always have it with Vegemite and butter the next day.
To make the open-faced Vegemite treat you put on a nice lot of butter, and then you apply a thinner amout of Vegemite. You always want to be able to see the butter through the Vegemite. If you are on the go and simply in need of a quick good thing to throw down, you get a nice fresh piece of bread, apply the butter and Vegemite, and then fold it in half and you're good to go. It can also be applied to toast, and in particular toasted English muffins or crumpets.
a final note: The English have a similar product called Marmite. The two are not interchangeable! I will tolerate Marmite, but I'd probably pass. I can't put my finger on it, but they just aren't the same despite looking the same. It's kind of like the coke and pepsi dispute. I love coke and really don't like pepsi.