In a small bowl, combine the yeast, sugar and warm water and let it sit for 5 minutes until foamy.

In a large bowl, mix together the flour and salt. Add in the melted butter or margarine and stir until combined. Pour in the yeast mixture and knead by hand until you have a smooth and elastic dough.

Transfer the dough to a lightly floured surface and roll it out into a rectangle, about ½ inch thick. Spread the vegemite over the surface of the dough, leaving a ¼-inch border around the edges. Roll up the dough tightly from one end until you have a long log shape.

Cut the log into 2cm slices and arrange them on a baking tray lined with parchment paper. Bake in an oven preheated to 200 degrees Celsius for 20 minutes, until golden brown. Let cool before serving. Enjoy!