Step by step method

1. Mix everything together in your mixer (excluding the egg white) with a dough hook until you get a nice, really smooth dough.
2. This can take a while (15 minutes, scraping down the dough every few minutes from the dough hook in the mixer).
3. After it's mixed, place the dough in a lightly oiled bowl, turn to coat (so it won't dry out), cover then let it rise in a draft-free place until doubled in size.
4. This might take as much as 2 hours since the large amount of fat will slow the rise.
5. After rising, knock back the dough, cut it into about 12 equal pieces and press them fairly flat.
6. Roll the dough into a round shape and place on parchment paper to rise, covered for about 45 minutes. If you want, you can instead place the filled dough balls in a lightly greased muffin tray to maintain the round shape.
7. Let the dough rise in the tray until they overflow the tops a little to make the traditional 'mushroom' top.
8. Preheat the oven to 185°C.
9. Just before placing in the oven, brush gently with a wash of egg white and water.
10. Sprinkle with sesame seeds if you want.
11. Bake for 10 minutes, turn them 180°C for even baking, then bake another 10 minutes.