Mix warm water, yeast, and sugar into stand mixer bowl.
Let stand for 5-10 minutes until frothy.
Meanwhile whisk plain flour and wholewheat flour together in a separate bowl.
When yeast is bubbly and active, add in sea salt, 1 tbsp rosemary, 1 tbsp olive oil into mixture.
Turn on mixer fitted with dough hook on low, and slowly add in flour.
When incorporated, allow to knead on low for 1-2 minutes, then medium speed for 5 minutes.
Or you can hand knead which will take about 10-12 minutes.
The dough should appear smooth and pull of the sides.
Grease a mixing bowl with olive oil, and transfer dough into the bowl flipping once to coat it with oil.
Cover with cling wrap or damp towel, and allow it to rise until double in size. About 1 hour.
Punch it down, divide dough into 2, shape into round loaves, and place on baking sheet lined with parchment paper.
Sprinkle the remaining 1 tbsp rosemary, and pat it on to make sure it sticks on the loaves.
Cover and allow to rise again until doubled. (45 minutes)
Bake in preheated oven for 15-20 minutes at 190C, until golden.
Remove from oven, brush on melted butter and sprinkle sea salt flakes.
Transfer to wire rack to cool.
Serve with olive oil & crack black pepper, and/or olive oil with balsamic vinegar for dipping.