In a small bowl, combine olive oil and rosemary - set aside
Pour yeast into 120ml of warm water. Stir to dissolve the yeast and let stand for 5 to 10 minutes.
In a medium size bowl, mix the flour with the salt. Add the yeast and olive oil rosemary mix to the flour.
Using a wooden spoon, mix well until you have a rough dough, then transfer to a clean flour dusted work surface and knead for around 10 minutes, or until soft and springy.
Return the dough to an oiled bowl, cover with plastic wrap and leave to rise in a warm place until double the size (about 1 hour).
Divide the dough into 4 (for burger buns) or 6 (for regular dinner rolls) equal pieces and roll each into balls. Evenly space them out on a lined baking tray.
Cover again with plastic wrap and leave in a warm place for a further 30 minutes.
Preheat the oven to 450F (230C).
Brush the buns with some olive oil and sprinkle more chopped rosemary on top (optional).
Bake at 450F for 10 minutes. Reduce heat to 375F and bake an additional 10 to 15 minutes, until browned and sound hollow when tapped.
Remove to wire rack to cool.