Toast. Until it's almost burnt.
Butter.
Solid thin layer of vegemite to cover every possible millimeter. Similar to this

Note: I have many, many years of building up vegemite resistance. Newcomers to vegemite should never attempt this. Beginners start with at most something like this instead. Lots of people like even less than that. Start with less; you can always add a little bit more on.

Also, very occasionally, if I don't feel hungry but feel like I should have something, a vegemite sandwich hits the spot. The softer the bread, the better. I don't put as much vegemite on as on my toast. So, it's almost a butter sandwich with a slight vegemite flavour.

The last way I'll have vegemite is on crackers. The crackers must have holes in them, and you must put one on top of the other so that you can squeeze it to make the delicious butter & vegemite worms pop out. Which you instantly lick off. Vita Weats used to do the job well. Recommend butter on both crackers, but vegemite only on the bottom cracker, otherwise you have too much vegemite!

Fun fact: Since 2017, Vegemite is now owned by the Bega group, not Kraft. Bega Group is a public company and close to half of the shares are still held by Bega's farmer-suppliers, while the rest are owned by public investors

Ideally on a crumpet with a ton of butter, or between 2 bits of toast with a slice of cheese.

Fun story - when I was newly married in the states I had a jar sent over and she decided to treat me by making me a piece of Vegemite toast. With no Vegemite experience, she slathered it on there like it was peanut butter, I swear she used half the jar! 🤣 I tried to choke it down, but had to come clean and teach her how Vegemite works. Been married 20 years and she still won't eat it!

On a sandwich spread so thick it looks like there’s a third slice of bread.

50/50 with butter on toast with a cup of black coffee. It's great this way, especially if you get the butter on first to let it melt on the toast while you wrestle the Vegemite out.

I like marmite. How similar are they? I tend to spread marmite on buttered toast or - even better - a pan toasted crumpet.

The word "drizzle" doesn't really work for Vegemite. It's pretty solid unlike jam or honey and can only be spread, not drizzled.

How I have it: medium toast. A heavy spread of butter or margarine. Then a heavy but specifically uneven spread of Vegemite. Parts of it should have roughly as much Vegemite as usually recommended to newcomers. But parts should be a thick mixture of the Vegemite and butter that might be as much as 4 mm thick.

I used to do butter, vegemite and cheese sandwiches. Plain or toasted.

It's good on toast with some kind of dairy (butter or cheese) to temper it a bit. Surprise friends by including it on your next charcuterie presentation

With marg on crackers or toast

But there is Vegemite pasta https://www.notquitenigella.com/2011/03/15/meeting-nigella-lawson-vegemite-spaghetti/

You can also stir plain flour or cornflour into pan drippings then chuck in Vegemite and water to make gravy

On toast, with avocado

On an english muffin with butter, salami and cheese.